HJKL is a rectangle which has a breadth of 12 cm. It is divided into 4 triangles. Triangle M is
112 of the area of the rectangle and
13 the area of Triangle P. Triangle N has an area of 58 cm
2.
- Find the area of the rectangle.
- Find the perimeter of the rectangle.
M |
N |
P |
Rectangle |
1 |
|
|
12 |
1 |
|
3 |
|
1 u |
2 u |
3 u |
12 u |
(a)
Area of Triangle N
= Half of Rectangle HJKL - Triangle P - Triangle M
= (12 u ÷ 2) - 1 u - 3 u
= 2 u
2 u = 58
1 u = 58 ÷ 2 = 29
Area of the rectangle
= 12 u
= 12 x 29
= 348 cm
2 (b)
Length of the rectangle
= 348 ÷ 12
= 29 cm
Perimeter of the rectangle
= 29 x 2 + 12 x 2
= 82 cm
Answer(s): (a) 348 cm
2; (b) 82 cm