PSLE Figure 1 shows a trapezium which has a perimeter of 74 cm. Gabby joins three such trapeziums to form Figure 2 which has a perimeter of 158 cm.
- Find the length of AB.
- Gabby joins another four such trapeziums to form Figure 3 which has an area of 1248 cm2. Find the length of XY.
(a)
Perimeter of three separate trapeziums
= 3 x 74
= 222 cm
Number of overlapping ABs = 4
Length of 4 ABs
= 222 - 158
= 64 cm
Length of 1 AB
= 64 ÷ 4
= 16 cm
(b)
Area of 2 rectangles
= 1248 ÷ 2
= 624 cm
2 Length of the rectangle
= 624 ÷ 16
= 39 cm
Length of XY
= 39 - 16 - 11
= 12 cm
Answer(s): (a) 16 cm; (b) 12 cm