The figure is made up of identical quadrants. The radius is 18 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 18 x 18
= 1017.36 cm
2 Area of
12 shaded leaf
= (1017.36 ÷ 4) - (
12 x 18 x 18)
= 92.34 cm
2 Area of four
12 shaded leaf
= 92.34 x 4
= 369.36 cm
2 Area of the shaded part
= 1017.36 + 369.36
= 1386.72 cm
2 (b)
Length of combined curved lines
= 3.14 x 18 x 2 x 2
= 226.08 cm
Length of 12 straight lines
= 18 x 12
= 216 cm
Perimeter of the shaded part
= 226.08 + 216
= 442.08 cm
Answer(s): (a) 1386.72 cm
2; (b) 442.08 cm