因为：外圆直径是内圆直径的1.5倍所以：外圆半径是内圆半径的1.5倍,即：R=1.5r圆环面积=3.14(R2-r^2)=3.14[(1.5r)^2-r^2]=3.14*1.25r^2=150r^=120/3.14外圆面积=3.14R^2=3.14(1.5r)^2=3.14*2.25*120/3.14=270平方分...