PSLE A symmetric figure is drawn on a rectangular piece of paper 176 cm by 110 cm as shown. Its outline consists of a large semicircle, 4 smaller semicircles and 2 straight lines.
- What is the area of the figure?
- What is its perimeter? Take π = 3.14
(a)
Radius of the large semicircle
= 176 ÷ 2
= 88 cm
Area of the large semicircle
=
12 x 3.14 x 88 x 88
= 12158.08 cm
2 Breadth of the small rectangle
= 110 - 88
= 22 cm
Area of the small rectangle
= 176 x 22
= 3872 cm
2 Area of the 4 smaller semicircles
= 2 x 3.14 x 22 x 22
= 3039.52 cm
2 Area of the 8 boomerangs
= 3872 - 3039.52
= 832.48 cm
2 Area of the figure
= 832.48 + 12158.08
= 12990.56 cm
2 (b)
Circumference of the curved lines
= 3.14 x 176
= 552.64 cm
Perimeter of the figure
= 552.64 + 22 + 22
= 596.64 cm
Answer(s): (a) 12990.56 cm
2; (b) 596.64 cm