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
= 12 ÷ 2
= 6 cm
Radius of the large quarter circle
= 12 + 6
= 18 cm
(b)
Circumference of each large quarter
=
14 x 2 x 3.14 x 18
= 28.26 cm
Circumference of each small quarter circle
=
14 x 2 x 3.14 x 12
= 18.84 cm
Perimeter of the shaded figure
= 2 x 28.26 + 3 x 18.84 + 2 x 6 + 12
= 56.52 + 56.52 + 24
= 137.04 cm
Answer(s): (a) 18 cm; (b) 137.04 cm