The figure is made up of a circle, a rectangle and 2 semicircles. HK, the diameter of the circle, is 125 cm, HJ is 120 cm and JK is 35 cm.

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 HJ
= 120 ÷ 2 
= 60 cm

Area of Semicircle HJ
= ¹₂ x 60 x 60 x 3.14
= 5652 cm²

Radius of JK
= 35 ÷ 2
= 17.5 cm

Area of Semicircle JK
= ¹₂ x 17.5 x 17.5 x 3.14
= 480.8125 cm²

Radius of HK
= 125 ÷ 2
= 62.5 cm

Area of the semicircle HK = Radius HK
= ¹₂ x 62.5 x 62.5 x 3.14
= 6132.8125 cm²

Total area of shaded parts
= 5652 + 480.8125 + ¹₂ x 120 x 35 - 6132.8125
= 2100 cm²

(b)
Length of Semicircle HJ
= ¹₂ x 3.14 x 120
= 188.4 cm

Length of Semicircle JK
= ¹₂ x 3.14 x 35
= 54.95 cm

Length of Semicircle HK
= ¹₂ x 3.14 x 125
= 196.25 cm

Perimeter of shaded parts
= 188.4 + 54.95 + 196.25 
= 5652 cm

Answer(s): (a) 2100 cm²; (b) 5652 cm