Question

PQRS is a diameter of a circle of radius 6cm. the lengths PQ , QR , and RS are equal .Semicircles are drawn on PQ and QS as diameters. Find the perimeter of the shaded region ??

Answer 1

`r=6 \\d=2r=12 \\PQ=QR=RS= (d)/(3) = (12)/(3) =4 \\ \\P= (1)/(2)* 2r\pi+(1)/(2)* 2* QR*\pi+(1)/(2)* 2 (PQ)/(2) \pi \\ \\P=r\pi+QR*\pi+(PQ)/(2) \pi \\ \\P=6\pi+4\pi+(4)/(2) \pi \\ \\P=12\pi`