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
= 25 ÷ 2
= 12.5 cm
Radius of the large quarter circle
= 25 + 12.5
= 37.5 cm
(b)
Circumference of each large quarter
=
14 x 2 x 3.14 x 37.5
= 58.875 cm
Circumference of each small quarter circle
=
14 x 2 x 3.14 x 25
= 39.25 cm
Perimeter of the shaded figure
= 2 x 58.875 + 3 x 39.25 + 2 x 12.5 + 25
= 117.75 + 117.75 + 50
= 285.5 cm
Answer(s): (a) 37.5 cm; (b) 285.5 cm