PSLE In Figure 1, VWXY is a rectangular piece of paper. After 8 identical triangles are cut out from the paper, the remaining paper is shown in Figure 2. The area of the remaining paper is 460 cm
2.
- What is the area of each triangle that was cut out?
- The perimeter of Figure 2 is 72 cm longer than the perimeter of Figure 1. What is the perimeter of each triangle?
(a)
Area of Rectangle VWXY
= 27 x 20
= 540 cm
2 Area of the 8 triangles
= 540 - 460
= 80 cm
2 Area of each triangle that was cut out
= 80 ÷ 8
= 10 cm
2 (b)
Perimeter of Rectangle VWXY
= 2(27 + 20)
= 2 x 47
= 94 cm
Perimeter of Figure 2
= 94 + 72
= 166 cm
Sum of the lengths of all the jagged edges
= 166 - (2 x 27)
= 166 - 54
= 112 cm
Sum of the lengths of the jagged edges of 1 triangle
= 112 ÷ 8
= 14 cm
Base of each triangle
= 20 ÷ 4
= 5 cm
Perimeter of each triangle
= 14 + 5
= 19 cm
Answer(s): (a) 10 cm
2; (b) 19 cm