PSLE The outline of the shaded figure is formed by 3 identical small quarter circles, 2 identical large quarter circles and 3 straight lines. Take π = 3.14
- What is the radius of the large quarter circle?
- Find the perimeter of the shaded figure.
(a)
Length of AB
= Length of BC
= 20 ÷ 2
= 10 cm
Radius of the large quarter circle
= 20 + 10
= 30 cm
(b)
Circumference of each large quarter
=
14 x 2 x 3.14 x 30
= 47.1 cm
Circumference of each small quarter circle
=
14 x 2 x 3.14 x 20
= 31.4 cm
Perimeter of the shaded figure
= 2 x 47.1 + 3 x 31.4 + 2 x 10 + 20
= 94.2 + 94.2 + 40
= 228.4 cm
Answer(s): (a) 30 cm; (b) 228.4 cm