LMNP is a rectangle which has a breadth of 11 cm. It is divided into 4 triangles. Triangle Q is
111 of the area of the rectangle and
13 the area of Triangle S. Triangle R has an area of 37.5 cm
2.
- Find the area of the rectangle.
- Find the perimeter of the rectangle.
Q |
R |
S |
Rectangle |
1 |
|
|
11 |
1 |
|
3 |
|
1 u |
1.5 u |
3 u |
11 u |
(a)
Area of Triangle R
= Half of Rectangle LMNP - Triangle S - Triangle Q
= (11 u ÷ 2) - 1 u - 3 u
= 1.5 u
1.5 u = 37.5
1 u = 37.5 ÷ 1.5 = 25
Area of the rectangle
= 11 u
= 11 x 25
= 275 cm
2 (b)
Length of the rectangle
= 275 ÷ 11
= 25 cm
Perimeter of the rectangle
= 25 x 2 + 11 x 2
= 72 cm
Answer(s): (a) 275 cm
2; (b) 72 cm