天气预报15天查询> 教育> 圆面积的推导过程

圆面积的推导过程

更新时间: 2021-02-21 00:38:26     

圆周长(c):圆的直径(D),那圆的周长(c)除以圆的直径(D)等于π,那利用乘法的意义,就等于 π乘圆的直径(D)等于圆的周长(C),C=πd。而同圆的直径(D)是圆的半径(r)的两倍,所以就圆的周长(c)等于2乘以π乘以圆的半径(r),C=2πr。把圆平均分成若干份,可以拼成一个近似的长方形。长方形的宽就等于圆的半径(r),长方形的长就是圆周长(C)的一半。长方形的面积是ab,那圆的面积就是:圆的半径(r)的平方乘以π。

关键词: 面积 推导 过程

如有意见、反馈、侵权或投诉等情况,请联系:

电话:
邮箱:

我们将会在48小时内给与处理!

版权所有 Copyright ? 2009-2020 tianqiyubao3.com

页面:/news/view-3158536/ | 耗时:0.7325 s | 内存:1.89 MB | 查询:5 | 缓存读取:4 写入:1 | 加载文件:23
select * from tbl_Articles WHERE ArticleID=3158536 LIMIT 0,1
select * from tbl_Articles_data WHERE ArticleID=3158536 LIMIT 0,1
SELECT * FROM tbl_categories where CategoryID=90001 LIMIT 0,1
select * from tbl_Articles_sphinx where id=3158536 LIMIT 0,1
SELECT ArticleID,Title FROM tbl_Articles WHERE ArticleID IN(1213297,376015,2827574,86944,372096,1091719,86090,371405,1102787,100382,1107106,371109,1737308,1098931,1119023,369601,1310242,541960,376888,79993,100385,362379,86644,376095,86084,428941,1304635,369239,373427,359512) ORDER BY field (ArticleID,1213297,376015,2827574,86944,372096,1091719,86090,371405,1102787,100382,1107106,371109,1737308,1098931,1119023,369601,1310242,541960,376888,79993,100385,362379,86644,376095,86084,428941,1304635,369239,373427,359512)