The figure is not drawn to scale. CD//FE and ED//GC. Triangles CGD and DEF are isosceles triangles. Find
- ∠x
- ∠y.
(a)
∠DEF = ∠DCG = 70° (ED//GC, DC//EF)
∠CDG
= (180° - 70°) ÷ 2
= 110° ÷ 2
= 55° (Isosceles triangle)
∠EDF
= 180° - 70° - 70°
= 40° (Isosceles triangle)
∠x
= 180° - 70° - 55° - 40°
= 15° (Interior angles, DC//EF)
(b)
∠y
= 180° - 30° - 15°
= 135° (Angles sum of triangle)
Answer(s): (a) 15°; (b) 135°