10÷2=5(厘米),
8÷2=4(厘米),
3.14×(52-42),
=3.14×(25-16),
=3.14×9,
=28.26(平方厘米).
答:圆环的面积是28.26平方厘米.
故答案为:28.26.
一个圆环,内圆直径是8cm,外圆直径是10cm,则圆环的面积是_cm2.
一个圆环,内圆直径是8cm,外圆直径是10cm,则圆环的面积是______cm2.
数学人气:375 ℃时间:2019-09-29 03:13:46
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