Question

这道题怎么做？求求大家帮帮忙，拜托了T_T

Answer 1

如图，大半圆的半径是 3dm，小半圆的半径是 3dm×1/3=1dm

面积   = π×3×3÷2   -  π×1×1÷2   =

Answer 2

环宽2/3×3=2㎝
大圆半径3㎝，小圆半径3-2=1㎝
面积=½π(3²-1²)=4π

追答

环宽2/3×3=2dm
大圆半径3dm，小圆半径3-2=1dm
面积=½π(3²-1²)=4πdm²