The figure is made up of identical quadrants. The radius is 21 cm long. Take π as 3.14.
- Find the area of the shaded part.
- Find the perimeter of the shaded part.
(a)
Area of one circle
= 3.14 x 21 x 21
= 1384.74 cm
2 Area of
12 shaded leaf
= (1384.74 ÷ 4) - (
12 x 21 x 21)
= 125.685 cm
2 Area of four
12 shaded leaf
= 125.685 x 4
= 502.74 cm
2 Area of the shaded part
= 1384.74 + 502.74
= 1887.48 cm
2 (b)
Length of combined curved lines
= 3.14 x 21 x 2 x 2
= 263.76 cm
Length of 12 straight lines
= 21 x 12
= 252 cm
Perimeter of the shaded part
= 263.76 + 252
= 515.76 cm
Answer(s): (a) 1887.48 cm
2; (b) 515.76 cm