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【319907】三年级下册数学单元专项复习拔高卷 5.面积(含答案)

时间:2025-01-07 23:45:20 作者: 字数:9078字
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5.面积

一.选择题(满分16分,每小题2分)

1.一个长方形长20分米,宽5分米,它的面积是 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

A100分米 B60平方米 C100平方分米

2.用三个小正方形拼成一个长方形,拼成的长方形的长是9厘米,则这个长方形的面积是 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 平方厘米.

A36 B27 C18

3.张大伯用24米长的篱笆靠一面墙围成一个长方形的养鸡栏(如图),要想围得鸡栏面积最大,最大面积是 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 平方米.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

A64 B36 C72

4.一个长方形的长和宽各增加 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,增加的面积 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

A.大于25 B.等于25 C.小于25

5.可用以下那个算式计算长方形的面积? <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

A.长 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> B.长 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>  <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> C.长 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> D.(长 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 宽) <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

6.一个长方形桌面的面积是96平方分米,它的宽是8分米,长是 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

A12分米 B40分米 C88分米

7.一个长是6米,宽是长的一半,则这个长方形的宽是 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,面积是 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

A3 B12平方米 C18平方米

8.一根铁丝围成了一个长是9厘米,宽是5厘米的长方形,再用这铁丝围城一个正方形的面积是 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 平方厘米.

A14 B49 C28 D24

二.填空题(满分16分,每小题2分)

9.长方形面积36平方厘米,如果长不变,宽从5厘米增加到10厘米,现在面积是   

10.一个长方形的宽是25米,比长少7米,长是   米,面积是   平方米.

11.教室宽6米,面积是48平方米,教室长   米.

12400平方分米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    平方米

9平方分米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>    平方厘米.

13.用121分米长的小棒围城一个正方形,这个正方形的面积是   平方分米.

14.一个正方形和一个8分米、宽2分米的长方形的周长相等,这个正方形的面积是   

15.边长是   的正方形面积是1平方米,边长是2厘米的正方形面积是   

16.一个正方形的边长为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,如果边长增加到原来的3倍,新的正方形面积比原来增加    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,周长增加    <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

三.判断题(满分8分,每小题2分)

174平方分米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 平方厘米.   

18.某教室的面积约 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,用边长为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 的方砖铺地,至少需要140块.   

19.用32米长的篱笆围一个四边形的养鸡场,养鸡场的面积最大64平方米.   

20.正方形的边长扩大10倍,它的面积就扩大100倍.   

四.计算题(满分12分,每小题6分)

21.(6分)张伯伯和李爷爷各买了同样长的篱笆,每人围了一个菜园.请你帮忙计算一下,两个菜园的面积分别是多少?

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

22.(6分)计算如图各图形的面积.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

五.操作题(满分12分,每小题6分)

23.(6分)用红色彩笔描出下面每个物体或图形的一周再用黄色彩笔涂出它们的面积. <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

24.(6分)画一个面积是2平方厘米的正方形,留下画图的痕迹.

六.解答题(满分36分,每小题6分)

25.(6分)一块足球场地长108米,宽比长短40米,这块足球场地的面积是多少平方米?

26.(6分)有一块长15米、宽12米的草地,草地占地面积是多少平方米?在草地四周围上护栏,护栏长多少米?

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

27.(6分)教室前面的墙长7米,宽4米,墙上有一块面积是4平方米的黑板,要粉刷教室前面墙的面积,粉刷面积是多少?

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

28.(6分)要给一个长 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 、宽 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 的广场铺上边长为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 的大理石方砖,至少需要多少块砖?如果每平方米材料与工时费共计300元,需要多少钱?

29.(6分)李阿姨家有块长方形的油菜田,长 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,宽 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,如果每平方米收油菜籽2千克,这块田可以收油菜籽多少千克?

30.(6分)张晓明打算用铁丝围一个面积是96平方厘米的长方形(长和宽都是整厘米数).他可以怎样围?在表中填一填.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 厘米







 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 厘米







参考答案

一.选择题(满分16分,每小题2分)

1解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方分米);

答:它的面积是100平方分米.

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

2解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方厘米)

答:这个长方形的面积是27平方厘米,

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

3解:设长方形的宽为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,则它的长为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

因为长方形的长和宽越接近,则其面积越大.

所以长方形的宽应是6米,长是12米,

则此长方形的面积为: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米).

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

4解:因为长方形的长和宽各增加 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 后,

增加部分由两个面积相等的长方形和一个边长为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 的正方形组成,

所以增加部分的面积应大于正方形的面积,

即大于 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方厘米);

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

5解:长方形的面积是长与宽的积,要求长方形的面积,就要知道它的长和宽.

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

6解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (分米),

答:长方形的长是12分米.

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

7解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米)

答:这个长方形的宽是3米,面积是18平方米.

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

8解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (厘米)

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方厘米)

答:再用这铁丝围城一个正方形的面积是49平方厘米.

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

二.填空题(满分16分,每小题2分)

9解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方厘米)

答:现在的面积是72平方厘米.

答案:72平方厘米.

10解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米)

答:长是32米,面积是800平方米.

答案:32800

11解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

答:教室长8米.

答案:8

12解:(1400平方分米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 平方米;

29平方分米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 平方厘米.

答案:4900

13解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (分米)

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方分米)

答:这个正方形的面积是9平方分米.

答案:9

14解:正方形周长:

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (分米),

面积:

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方分米),

答;正方形的面积是25平方分米.

答案:25平方分米.

15解:因为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,所以边长是1米的正方形面积是1平方米,

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方厘米),

答:边长是1米的正方形面积是1平方米,边长是2厘米的正方形的面积是4平方厘米.

答案:1米,4平方厘米.

16解:边长增加到原来的3倍,即边长变为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (厘米)

所以新的正方形面积比原来增加:

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方厘米)

周长增加:

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (厘米)

答:新的正方形面积比原来增加 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,周长增加 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

答案:20040

三.判断题(满分8分,每小题2分)

17解:4平方分米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 平方厘米.

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

18解:50厘米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 米,

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (块 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

即至少需要240块,而不是140块.

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

19解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米)

答:养鸡场的面积最大64平方米.

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

20解:根据题意,假设这个正方形的边长是 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,面积 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

正方形的边长扩大10倍,它的边长 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> ,则面积 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

因为 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

所以正方形的边长扩大10倍,它的面积就扩大100倍.

答案: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

四.计算题(满分12分,每小题6分)

21解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米)

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米)

答:长方形菜园的面积是308平方米,正方形菜园的面积是576平方米.

22解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方分米)

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方厘米)

答:长方形的面积是300平方分米,正方形的面积是36平方厘米.

五.操作题(满分12分,每小题6分)

23解:

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

24解:以任意一点 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 为圆心,再用以点 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 为一个端点1厘米长的线段为半径画圆,进而画出这个圆的两条互相垂直的直径,依次连接两条直径的端点,即可画出这个圆的内接正方形如图所示:

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

这个正方形的面积是: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方厘米),

所以这个圆内接正方形就是面积为2平方厘米的正方形.

六.解答题(满分36分,每小题6分)

25解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米)

答:这块足球场地的面积是7344平方米.

26解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米),

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

答:草地占地面积是180平方米,护栏长54米.

27解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米);

答:粉刷的面积是24平方米.

28解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方米)

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (平方厘米)

6400平方厘米 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 平方米

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (块 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (元 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

答:至少需要12500块砖,需要2400000元钱.

29解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> (千克)

答:这块地今年一共可以收油菜籽240千克.

30解: <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a>

答案:

张晓明打算用铁丝围一个面积是96平方厘米的长方形(长和宽都是整厘米数).他可以怎样围?在表中填一填.

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 厘米

96

48

32

24

16

12

 <a href="/tags/1/" title="单元" class="c1" target="_blank">单元</a> <a href="/tags/14/" title="复习" class="c1" target="_blank">复习</a> <a href="/tags/46/" title="答案" class="c1" target="_blank">答案</a> <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/105/" title="面积" class="c1" target="_blank">面积</a> 厘米

1

2

3

4

6

8


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