题目内容
(2012?宝应县模拟)图形计算:
(1)已知下图的直径是20厘米,求它的面积和周长.
![](http://thumb.1010pic.com/pic3/upload/images/201206/19/5b053d18.png)
(2)计算下图的体积.
![](http://thumb.1010pic.com/pic3/upload/images/201206/19/297f840b.png)
(1)已知下图的直径是20厘米,求它的面积和周长.
![](http://thumb.1010pic.com/pic3/upload/images/201206/19/5b053d18.png)
(2)计算下图的体积.
![](http://thumb.1010pic.com/pic3/upload/images/201206/19/297f840b.png)
分析:(1)根据半圆的周长=圆的周长÷2+d,半圆的面积=πr2÷2,代入数据即可解答;
(2)根据圆柱的体积=底面积×高和圆锥的体积=
×底面积×高,代入数据即可解答.
(2)根据圆柱的体积=底面积×高和圆锥的体积=
1 |
3 |
解答:解:(1)周长为:3.14×20÷2+20,
=31.4+20,
=51.4(厘米);
面积为:3.14×(
)2÷2,
=3.14×100÷2,
=157(平方厘米);
答:半圆的周长是51.4厘米,面积是157平方厘米.
(2)3.14×(
)2×20,
=3.14×4×20,
=251.2;
×3.14×22×6,
=
×3.14×4×6,
=25.12;
答:圆柱的体积是251.2;圆锥的体积是25.12.
=31.4+20,
=51.4(厘米);
面积为:3.14×(
20 |
2 |
=3.14×100÷2,
=157(平方厘米);
答:半圆的周长是51.4厘米,面积是157平方厘米.
(2)3.14×(
4 |
2 |
=3.14×4×20,
=251.2;
1 |
3 |
=
1 |
3 |
=25.12;
答:圆柱的体积是251.2;圆锥的体积是25.12.
点评:此题考查了半圆的周长与面积计算方法以及圆柱与圆锥的体积公式的计算应用,要求学生熟记公式进行解答.
![](http://thumb2018.1010pic.com/images/loading.gif)
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