GHJK is a rectangle which has a breadth of 8 cm. It is divided into 4 triangles. Triangle L is
113 of the area of the rectangle and
14 the area of Triangle N. Triangle M has an area of 15 cm
2.
- Find the area of the rectangle.
- Find the perimeter of the rectangle.
L |
M |
N |
Rectangle |
1 |
|
|
13 |
1 |
|
4 |
|
1 u |
1.5 u |
4 u |
13 u |
(a)
Area of Triangle M
= Half of Rectangle GHJK - Triangle N - Triangle L
= (13 u ÷ 2) - 1 u - 4 u
= 1.5 u
1.5 u = 15
1 u = 15 ÷ 1.5 = 10
Area of the rectangle
= 13 u
= 13 x 10
= 130 cm
2 (b)
Length of the rectangle
= 130 ÷ 8
= 16.25 cm
Perimeter of the rectangle
= 16.25 x 2 + 8 x 2
= 48.5 cm
Answer(s): (a) 130 cm
2; (b) 48.5 cm