The figure is made up of a circle, a rectangle and 2 semicircles. WY, the diameter of the circle, is 25 m, WX is 20 m and XY is 15 m.

1. What is the total area of the shaded parts?
2. What is the total perimeter of the shaded parts? (Take π = 3.14)

(a)
Radius of WX
= 20 ÷ 2 
= 10 m

Area of Semicircle WX
= ¹₂ x 10 x 10 x 3.14
= 157 m²

Radius of XY
= 15 ÷ 2
= 7.5 m

Area of Semicircle XY
= ¹₂ x 7.5 x 7.5 x 3.14
= 88.3125 m²

Radius of WY
= 25 ÷ 2
= 12.5 m

Area of the semicircle WY = Radius WY
= ¹₂ x 12.5 x 12.5 x 3.14
= 245.3125 m²

Total area of shaded parts
= 157 + 88.3125 + ¹₂ x 20 x 15 - 245.3125
= 150 m²

(b)
Length of Semicircle WX
= ¹₂ x 3.14 x 20
= 31.4 m

Length of Semicircle XY
= ¹₂ x 3.14 x 15
= 23.55 m

Length of Semicircle WY
= ¹₂ x 3.14 x 25
= 39.25 m

Perimeter of shaded parts
= 31.4 + 23.55 + 39.25 
= 157 m

Answer(s): (a) 150 m²; (b) 157 m