PSLE Figure 1 shows a trapezium which has a perimeter of 81 cm. Nicole joins three such trapeziums to form Figure 2 which has a perimeter of 163 cm.
- Find the length of AB.
- Nicole joins another four such trapeziums to form Figure 3 which has an area of 1560 cm2. Find the length of XY.
(a)
Perimeter of three separate trapeziums
= 3 x 81
= 243 cm
Number of overlapping ABs = 4
Length of 4 ABs
= 243 - 163
= 80 cm
Length of 1 AB
= 80 ÷ 4
= 20 cm
(b)
Area of 2 rectangles
= 1560 ÷ 2
= 780 cm
2 Length of the rectangle
= 780 ÷ 20
= 39 cm
Length of XY
= 39 - 20 - 7
= 12 cm
Answer(s): (a) 20 cm; (b) 12 cm