有一个圆环,内圆周长是31.4cm,外圆周长是62.8cm,圆环的面积是多少过程
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有一个圆环,内圆周长是31.4cm,外圆周长是62.8cm,圆环的面积是多少过程
有一个圆环,内圆周长是31.4cm,外圆周长是62.8cm,圆环的面积是多少过程
有一个圆环,内圆周长是31.4cm,外圆周长是62.8cm,圆环的面积是多少过程
31.4/3.14/2=5cm
62.8/3.14/2=10cm
(102-52)*3.14=235.5cm178
答案补充
31.4/3.14/2=5cm
62.8/3.14/2=10cm
(102-52)*3.14=235.5cm2
内圆半径5cm外圆半径10cm
圆环的面积=3.14×(100-25)=235.5平方厘米
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R1=31.4/(3.14*2)=5cm
R2=62.8/(3.14*2)=10cm
S=Pi*(100-25)=75*3.14 平方厘米