苇子沟学校栾应强5米O·r=5m1m1m由此可推知圆的面积大约是3r24r22r2171819202122232425262728293031324235678910111213141516142356789101112131415161423567891011121314151611718192021222324252627282930313217181920212223242526272829303132123456789101112131415163231302928272625242322212019181712345678910111213141516123456789101112131415161234567891011121314151612345678910111213141516123456789101112131415161234567891011121314151612345678910111213141516123456789101112131415161234567891011121314151612345678910111213141516C÷2r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=2r2r圆的面积=长方形的面积=2C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
(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)389
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
100m60m