PSLE Figure 1 shows a trapezium which has a perimeter of 60 cm. Joelle joins three such trapeziums to form Figure 2 which has a perimeter of 124 cm.
- Find the length of AB.
- Joelle joins another four such trapeziums to form Figure 3 which has an area of 840 cm2. Find the length of XY.
(a)
Perimeter of three separate trapeziums
= 3 x 60
= 180 cm
Number of overlapping ABs = 4
Length of 4 ABs
= 180 - 124
= 56 cm
Length of 1 AB
= 56 ÷ 4
= 14 cm
(b)
Area of 2 rectangles
= 840 ÷ 2
= 420 cm
2 Length of the rectangle
= 420 ÷ 14
= 30 cm
Length of XY
= 30 - 14 - 7
= 9 cm
Answer(s): (a) 14 cm; (b) 9 cm