The figure is not drawn to scale. CD//FE and ED//GC. Triangles CGD and DEF are isosceles triangles. Find
- ∠q
- ∠r.
(a)
∠DEF = ∠DCG = 70° (ED//GC, DC//EF)
∠CDG
= (180° - 70°) ÷ 2
= 110° ÷ 2
= 55° (Isosceles triangle)
∠EDF
= 180° - 70° - 70°
= 40° (Isosceles triangle)
∠q
= 180° - 70° - 55° - 40°
= 15° (Interior angles, DC//EF)
(b)
∠r
= 180° - 26° - 15°
= 139° (Angles sum of triangle)
Answer(s): (a) 15°; (b) 139°