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最佳答案:两个小半圆周长等于大半圆周长因为:记圆周率PI,大圆半径R,小圆半径r1,r22*(r1+r2)=2RPI*(r1+r2)=PI*R这个结论记住很好用
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最佳答案:there are fifty students in class one grade eight in yucai school