QRST is a rectangle which has a breadth of 8 cm. It is divided into 4 triangles. Triangle U is
113 of the area of the rectangle and
13 the area of Triangle W. Triangle V has an area of 45 cm
2.
- Find the area of the rectangle.
- Find the perimeter of the rectangle.
U |
V |
W |
Rectangle |
1 |
|
|
13 |
1 |
|
3 |
|
1 u |
2.5 u |
3 u |
13 u |
(a)
Area of Triangle V
= Half of Rectangle QRST - Triangle W - Triangle U
= (13 u ÷ 2) - 1 u - 3 u
= 2.5 u
2.5 u = 45
1 u = 45 ÷ 2.5 = 18
Area of the rectangle
= 13 u
= 13 x 18
= 234 cm
2 (b)
Length of the rectangle
= 234 ÷ 8
= 29.25 cm
Perimeter of the rectangle
= 29.25 x 2 + 8 x 2
= 74.5 cm
Answer(s): (a) 234 cm
2; (b) 74.5 cm