if a wire is bent into the shape of a square then the area of the square is 81cm2 when the wire is bent into semi circular shape then the area of the semicircular will be

Hey dude, area of sq=81, so side=9cm. So perimeter is 9×4=36cm. Thus the length of the wire is 36cm. And thus the perimeter of semicircle is 36cm. I'll leave the remaining for you.