六年级数学圆的面积课件.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,圆的面积,苇子沟学校 栾应强,5,米,O,r,=5m,1m,1m,由此可推知圆的面积,大约,是,r,2,4,r,2,2,r,2,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,4,2,3,5,6,7,8,9,10,11,12,13,14,15,16,1,4,2,3,5,6,7,8,9,10,11,12,13,14,15,16,1,4,2,3,5,6,7,8,9,10,11,12,13,14,15,16,1,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,32,31,30,29,28,27,26,25,24,23,22,21,20,19,18,17,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,C2,r,宽,长,长方形的长,=,圆周长的一半,=,长方形的宽,=,圆的半径,=r,长方形的面积,=,圆的面积,=,长方形的面积,=,做一做：,根据下面所给的条件，求圆的面积。,1,、半径,3,厘米,2,、直径,0.2,分米,3,、周长,6.28,米,试一试：,半径,1,米的圆有多大？能站几个人？,(,每个人站的时候占地面积为,0.2,平方米）,半径（,cm,）,直径（,cm,）,圆的周长,（,cm,）,圆的面积,（,cm,）,3,8,9.42,做一做,：,鹏辉小学准备扩建操场，设计,图如下,求操场的占地面积。,100m,60m,