The figure is not drawn to scale. XZAB is a trapezium and XZ // BA. Given that XB = XY, ∠BXY = 72° and ∠XZA = 103°.
- Find ∠ZAB
- Find ∠XYB
- Find ∠YBA
(a)
∠ZAB
= 180° - 103°
= 77° (Interior angles, XZ//BA)
(b)
∠XYB
= (180° - 72°) ÷ 2
= 108° ÷ 2
= 54° (Isosceles triangle)
(c)
∠YBA
= ∠XYB
= 54° (Alternate angles, XZ//BA)
Answer(s): (a) 77°; (b) 54°; (c) 54°