The figure is made up of a circle, a rectangle and 2 semicircles. LN, the diameter of the circle, is 10 m, LM is 8 m and MN is 6 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 LM
= 8 ÷ 2 
= 4 m

Area of Semicircle LM
= ¹₂ x 4 x 4 x 3.14
= 25.12 m²

Radius of MN
= 6 ÷ 2
= 3 m

Area of Semicircle MN
= ¹₂ x 3 x 3 x 3.14
= 14.13 m²

Radius of LN
= 10 ÷ 2
= 5 m

Area of the semicircle LN = Radius LN
= ¹₂ x 5 x 5 x 3.14
= 39.25 m²

Total area of shaded parts
= 25.12 + 14.13 + ¹₂ x 8 x 6 - 39.25
= 24 m²

(b)
Length of Semicircle LM
= ¹₂ x 3.14 x 8
= 12.56 m

Length of Semicircle MN
= ¹₂ x 3.14 x 6
= 9.42 m

Length of Semicircle LN
= ¹₂ x 3.14 x 10
= 15.7 m

Perimeter of shaded parts
= 12.56 + 9.42 + 15.7 
= 25.12 m

Answer(s): (a) 24 m²; (b) 25.12 m