解 大半圆的·面积=π(1.5d)平方/2=2.25d方π/2
小半圆的面积=π(1/2 d)方/2=1/4 d方π/2=d方π/8
中半圆的面积=πd方/2
∴阴影的面积=2.25d方π/2--πd方/2+ d方π/8
=9d方π/8-4d方π/8+d方π/8
=6d方π/8=3d方π/4=3πd方/4
解 大半圆的·面积=π(1.5d)平方/2=2.25d方π/2
小半圆的面积=π(1/2 d)方/2=1/4 d方π/2=d方π/8
中半圆的面积=πd方/2
∴阴影的面积=2.25d方π/2--πd方/2+ d方π/8
=9d方π/8-4d方π/8+d方π/8
=6d方π/8=3d方π/4=3πd方/4