NPQR is a rectangle which has a breadth of 10 cm. It is divided into 4 triangles. Triangle S is
113 of the area of the rectangle and
13 the area of Triangle U. Triangle T has an area of 55 cm
2.
- Find the area of the rectangle.
- Find the perimeter of the rectangle.
S |
T |
U |
Rectangle |
1 |
|
|
13 |
1 |
|
3 |
|
1 u |
2.5 u |
3 u |
13 u |
(a)
Area of Triangle T
= Half of Rectangle NPQR - Triangle U - Triangle S
= (13 u ÷ 2) - 1 u - 3 u
= 2.5 u
2.5 u = 55
1 u = 55 ÷ 2.5 = 22
Area of the rectangle
= 13 u
= 13 x 22
= 286 cm
2 (b)
Length of the rectangle
= 286 ÷ 10
= 28.6 cm
Perimeter of the rectangle
= 28.6 x 2 + 10 x 2
= 77.2 cm
Answer(s): (a) 286 cm
2; (b) 77.2 cm