PSLE Figure 1 shows a trapezium which has a perimeter of 70 cm. Opal joins three such trapeziums to form Figure 2 which has a perimeter of 146 cm.
- Find the length of AB.
- Opal joins another four such trapeziums to form Figure 3 which has an area of 1152 cm2. Find the length of XY.
(a)
Perimeter of three separate trapeziums
= 3 x 70
= 210 cm
Number of overlapping ABs = 4
Length of 4 ABs
= 210 - 146
= 64 cm
Length of 1 AB
= 64 ÷ 4
= 16 cm
(b)
Area of 2 rectangles
= 1152 ÷ 2
= 576 cm
2 Length of the rectangle
= 576 ÷ 16
= 36 cm
Length of XY
= 36 - 16 - 9
= 11 cm
Answer(s): (a) 16 cm; (b) 11 cm