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
= 9 ÷ 2
= 4.5 cm
Radius of the large quarter circle
= 9 + 4.5
= 13.5 cm
(b)
Circumference of each large quarter
=
14 x 2 x 3.14 x 13.5
= 21.195 cm
Circumference of each small quarter circle
=
14 x 2 x 3.14 x 9
= 14.13 cm
Perimeter of the shaded figure
= 2 x 21.195 + 3 x 14.13 + 2 x 4.5 + 9
= 42.39 + 42.39 + 18
= 102.78 cm
Answer(s): (a) 13.5 cm; (b) 102.78 cm