PSLE Figure 1 shows a trapezium which has a perimeter of 52 cm. Sabrina joins three such trapeziums to form Figure 2 which has a perimeter of 108 cm.
- Find the length of AB.
- Sabrina joins another four such trapeziums to form Figure 3 which has an area of 624 cm2. Find the length of XY.
(a)
Perimeter of three separate trapeziums
= 3 x 52
= 156 cm
Number of overlapping ABs = 4
Length of 4 ABs
= 156 - 108
= 48 cm
Length of 1 AB
= 48 ÷ 4
= 12 cm
(b)
Area of 2 rectangles
= 624 ÷ 2
= 312 cm
2 Length of the rectangle
= 312 ÷ 12
= 26 cm
Length of XY
= 26 - 12 - 6
= 8 cm
Answer(s): (a) 12 cm; (b) 8 cm