如题所述
如图:
S△ = S3+S4+S5
S半圆(bc直径)=S2+S3+S5
S半圆(ab直径)=S1+S3+S4
则S圆 = S半圆(bc直径) + S半圆(ab直径) = S1+S2 + S3 + S3+S4+S5 = S1+S2 + S3 +S△
阴影部分面积=S1+S2+S3=S圆 -S△=π * 10 * 10 - 20 * 20 /2
=314-200
=114