PSLE In Figure 1, TUVW is a rectangular piece of paper. After 4 identical triangles are cut out from the paper, the remaining paper is shown in Figure 2. The area of the remaining paper is 360 cm
2.
- What is the area of each triangle that was cut out?
- The perimeter of Figure 2 is 64 cm longer than the perimeter of Figure 1. What is the perimeter of each triangle?
(a)
Area of Rectangle TUVW
= 25 x 20
= 500 cm
2 Area of the 4 triangles
= 500 - 360
= 140 cm
2 Area of each triangle that was cut out
= 140 ÷ 4
= 35 cm
2 (b)
Perimeter of Rectangle TUVW
= 2(25 + 20)
= 2 x 45
= 90 cm
Perimeter of Figure 2
= 90 + 64
= 154 cm
Sum of the lengths of all the jagged edges
= 154 - (2 x 25)
= 154 - 50
= 104 cm
Sum of the lengths of the jagged edges of 1 triangle
= 104 ÷ 4
= 26 cm
Base of each triangle
= 20 ÷ 2
= 10 cm
Perimeter of each triangle
= 26 + 10
= 36 cm
Answer(s): (a) 35 cm
2; (b) 36 cm