PSLE Figure 1 shows a trapezium which has a perimeter of 84 cm. Tiffany joins three such trapeziums to form Figure 2 which has a perimeter of 180 cm.
- Find the length of AB.
- Tiffany joins another four such trapeziums to form Figure 3 which has an area of 1548 cm2. Find the length of XY.
(a)
Perimeter of three separate trapeziums
= 3 x 84
= 252 cm
Number of overlapping ABs = 4
Length of 4 ABs
= 252 - 180
= 72 cm
Length of 1 AB
= 72 ÷ 4
= 18 cm
(b)
Area of 2 rectangles
= 1548 ÷ 2
= 774 cm
2 Length of the rectangle
= 774 ÷ 18
= 43 cm
Length of XY
= 43 - 18 - 12
= 13 cm
Answer(s): (a) 18 cm; (b) 13 cm