Question

In the given figure $APB$ and $CQD$ are semicircles of diameter $7cm$ each, while $ABC$ and $BSD$ are semicircles of diameter $14cm$ each. Find the perimeter of shaded region.

Answer 1

Perimeter of the shaded region= $APB+BSD+DQC+CA$

Length of the circumcircle=$\pi r$

$APB=CQD=7\pi /2$

$BSD=CA=14\pi /2$

Perimeter= $2\times 7\pi /2+2\times 14\pi /2=21\pi =66cm$