PSLE A symmetric figure is drawn on a rectangular piece of paper 44 cm by 33 cm as shown. Its outline consists of a large semicircle, 2 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
= 44 ÷ 2
= 22 cm
Area of the large semicircle
=
12 x 3.14 x 22 x 22
= 759.88 cm
2 Breadth of the small rectangle
= 33 - 22
= 11 cm
Area of the small rectangle
= 44 x 11
= 484 cm
2 Area of the 2 smaller semicircles
= 3.14 x 11 x 11
= 379.94 cm
2 Area of the 4 boomerangs
= 484 - 379.94
= 104.06 cm
2 Area of the figure
= 104.06 + 759.88
= 863.94 cm
2 (b)
Circumference of the curved lines
= 3.14 x 44
= 138.16 cm
Perimeter of the figure
= 138.16 + 11 + 11
= 160.16 cm
Answer(s): (a) 863.94 cm
2; (b) 160.16 cm