JKLM is a rectangle which has a breadth of 7 cm. It is divided into 4 triangles. Triangle N is
114 of the area of the rectangle and
14 the area of Triangle Q. Triangle P has an area of 20 cm
2.
- Find the area of the rectangle.
- Find the perimeter of the rectangle.
N |
P |
Q |
Rectangle |
1 |
|
|
14 |
1 |
|
4 |
|
1 u |
2 u |
4 u |
14 u |
(a)
Area of Triangle P
= Half of Rectangle JKLM - Triangle Q - Triangle N
= (14 u ÷ 2) - 1 u - 4 u
= 2 u
2 u = 20
1 u = 20 ÷ 2 = 10
Area of the rectangle
= 14 u
= 14 x 10
= 140 cm
2 (b)
Length of the rectangle
= 140 ÷ 7
= 20 cm
Perimeter of the rectangle
= 20 x 2 + 7 x 2
= 54 cm
Answer(s): (a) 140 cm
2; (b) 54 cm