LMNP is a rectangle which has a breadth of 5 cm. It is divided into 4 triangles. Triangle Q is
113 of the area of the rectangle and
13 the area of Triangle S. Triangle R has an area of 10 cm
2.
- Find the area of the rectangle.
- Find the perimeter of the rectangle.
Q |
R |
S |
Rectangle |
1 |
|
|
13 |
1 |
|
3 |
|
1 u |
2.5 u |
3 u |
13 u |
(a)
Area of Triangle R
= Half of Rectangle LMNP - Triangle S - Triangle Q
= (13 u ÷ 2) - 1 u - 3 u
= 2.5 u
2.5 u = 10
1 u = 10 ÷ 2.5 = 4
Area of the rectangle
= 13 u
= 13 x 4
= 52 cm
2 (b)
Length of the rectangle
= 52 ÷ 5
= 10.4 cm
Perimeter of the rectangle
= 10.4 x 2 + 5 x 2
= 30.8 cm
Answer(s): (a) 52 cm
2; (b) 30.8 cm