Question

In the picture PQRS is a square of side 10 cm. A, B, C and D are midpoints of the sides of the square

Semi circles are drawn inside the square.

a. Compute the area of the square.

b. Compute the area of the semi-circle.

c. Compute the area of the shaded part.

Answer 1

a. Since one side of the square is 10 cm,

Area = side x side = 10 × 10 = 100 cm²

b. The diameter of one semicircle = half of the side of the square

Diameter = 5 cm

∴ Radius = 5/2 cm

Since the four semicircles are equal. Area of the 4 semicircles

= Area of 2 circles = 2 × πr²

c. Area of the shaded part = Area of the square – Area of four semicircles.