Three semicircles each of diameter 3 cm, a circle of diameter 4.5 cm
Three semicircles each of diameter 3 cm, a circle of diameter 4.5 cm and a semicircle of radius 4.5 cm are drawn in the given figure. Find the area of the shaded region.
Answer
Area of semi-circle PQR = ½π(9/2)2
= 81π/8 cm2
Area of region circle, A = π(9/4)2
= 81π/16 cm2
Area of region (B + C) = π(3/2)2
= 9π/4 cm2
Area of region D = ½π(3/2)2
= 9π/8 cm2
Area of shaded region = Area of semicircle - Area of circle - Area of region (B + C) + Area of region D
= 81π/8 - 81π/16 - 9π/4 + 9π/8
= 63π/16 cm2
= 99/8 cm2