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
= 15 ÷ 2
= 7.5 cm
Radius of the large quarter circle
= 15 + 7.5
= 22.5 cm
(b)
Circumference of each large quarter
=
14 x 2 x 3.14 x 22.5
= 35.325 cm
Circumference of each small quarter circle
=
14 x 2 x 3.14 x 15
= 23.55 cm
Perimeter of the shaded figure
= 2 x 35.325 + 3 x 23.55 + 2 x 7.5 + 15
= 70.65 + 70.65 + 30
= 171.3 cm
Answer(s): (a) 22.5 cm; (b) 171.3 cm