JKLM is a rectangle which has a breadth of 10 cm. It is divided into 4 triangles. Triangle N is
113 of the area of the rectangle and
14 the area of Triangle Q. Triangle P has an area of 28.5 cm
2.
- Find the area of the rectangle.
- Find the perimeter of the rectangle.
N |
P |
Q |
Rectangle |
1 |
|
|
13 |
1 |
|
4 |
|
1 u |
1.5 u |
4 u |
13 u |
(a)
Area of Triangle P
= Half of Rectangle JKLM - Triangle Q - Triangle N
= (13 u ÷ 2) - 1 u - 4 u
= 1.5 u
1.5 u = 28.5
1 u = 28.5 ÷ 1.5 = 19
Area of the rectangle
= 13 u
= 13 x 19
= 247 cm
2 (b)
Length of the rectangle
= 247 ÷ 10
= 24.7 cm
Perimeter of the rectangle
= 24.7 x 2 + 10 x 2
= 69.4 cm
Answer(s): (a) 247 cm
2; (b) 69.4 cm