PSLE Figure 1 shows a trapezium which has a perimeter of 56 cm. Shiyun joins three such trapeziums to form Figure 2 which has a perimeter of 120 cm.
- Find the length of AB.
- Shiyun joins another four such trapeziums to form Figure 3 which has an area of 648 cm2. Find the length of XY.
(a)
Perimeter of three separate trapeziums
= 3 x 56
= 168 cm
Number of overlapping ABs = 4
Length of 4 ABs
= 168 - 120
= 48 cm
Length of 1 AB
= 48 ÷ 4
= 12 cm
(b)
Area of 2 rectangles
= 648 ÷ 2
= 324 cm
2 Length of the rectangle
= 324 ÷ 12
= 27 cm
Length of XY
= 27 - 12 - 7
= 8 cm
Answer(s): (a) 12 cm; (b) 8 cm