JKLM is a rectangle which has a breadth of 10 cm. It is divided into 4 triangles. Triangle N is
111 of the area of the rectangle and
13 the area of Triangle Q. Triangle P has an area of 21 cm
2.
- Find the area of the rectangle.
- Find the perimeter of the rectangle.
N |
P |
Q |
Rectangle |
1 |
|
|
11 |
1 |
|
3 |
|
1 u |
1.5 u |
3 u |
11 u |
(a)
Area of Triangle P
= Half of Rectangle JKLM - Triangle Q - Triangle N
= (11 u ÷ 2) - 1 u - 3 u
= 1.5 u
1.5 u = 21
1 u = 21 ÷ 1.5 = 14
Area of the rectangle
= 11 u
= 11 x 14
= 154 cm
2 (b)
Length of the rectangle
= 154 ÷ 10
= 15.4 cm
Perimeter of the rectangle
= 15.4 x 2 + 10 x 2
= 50.8 cm
Answer(s): (a) 154 cm
2; (b) 50.8 cm