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
= 13 ÷ 2
= 6.5 cm
Radius of the large quarter circle
= 13 + 6.5
= 19.5 cm
(b)
Circumference of each large quarter
=
14 x 2 x 3.14 x 19.5
= 30.615 cm
Circumference of each small quarter circle
=
14 x 2 x 3.14 x 13
= 20.41 cm
Perimeter of the shaded figure
= 2 x 30.615 + 3 x 20.41 + 2 x 6.5 + 13
= 61.23 + 61.23 + 26
= 148.46 cm
Answer(s): (a) 19.5 cm; (b) 148.46 cm