The perimeter of a square is equal to twice the perimeter of a rectangle of length 8cm and breadth 7cm. What is the circumference of a semicircle whose diameter is equal to the side of the square ?

We know that perimeter of rectangle = 2(l+b) = 2(8+7)= 30cm
Given perimeter of square is twice the perimeter of rectangle = 2(30) = 60cm
Therefore, side of the square is = 1/4 x 60 = 15cm
Circumference of the required semicircle =  $\mathrm{\pi r} + 2r$ =  $\frac{22}{7}\times \frac{15}{2} + 2\times \frac{15}{2}$ = 23.57 + 15 = 38.57cm.