圆环的外圆周长比内圆周长多25.12厘米,环宽是多少厘米?
人气：461 ℃ 时间：2019-11-09 01:56:41
解答
设外圆半径为R内圆半径为r 则：
2πR-2πr=25.12
2π(R-r)=25.12
R-r=4
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