The figure is not drawn to scale. XY//AZ and ZY//BX. Triangles XBY and YZA are isosceles triangles. Find
- ∠h
- ∠i.
(a)
∠YZA = ∠YXB = 72° (ZY//BX, YX//ZA)
∠XYB
= (180° - 72°) ÷ 2
= 108° ÷ 2
= 54° (Isosceles triangle)
∠ZYA
= 180° - 72° - 72°
= 36° (Isosceles triangle)
∠h
= 180° - 72° - 54° - 36°
= 18° (Interior angles, YX//ZA)
(b)
∠i
= 180° - 28° - 18°
= 134° (Angles sum of triangle)
Answer(s): (a) 18°; (b) 134°