The figure is not drawn to scale. PQ//SR and RQ//TP. Triangles PTQ and QRS are isosceles triangles. Find
- ∠a
- ∠b.
(a)
∠QRS = ∠QPT = 70° (RQ//TP, QP//RS)
∠PQT
= (180° - 70°) ÷ 2
= 110° ÷ 2
= 55° (Isosceles triangle)
∠RQS
= 180° - 70° - 70°
= 40° (Isosceles triangle)
∠a
= 180° - 70° - 55° - 40°
= 15° (Interior angles, QP//RS)
(b)
∠b
= 180° - 28° - 15°
= 137° (Angles sum of triangle)
Answer(s): (a) 15°; (b) 137°