In the figure, BCF and ECD are right-angled triangles. FC is parallel to ED. Find
- ∠CDE
- ∠CFE
(a)
∠ECF
= 360° - 90° - 90° - 120°
= 60° (Angles at a point)
∠CED = ∠ECF = 60° (Alternate angles)
∠CDE
= 180° - ∠ECD - ∠CED
= 180° - 90° - 60°
= 30° (Angles sum of triangle)
(b)
∠CFE
= 180° - ∠ECF - ∠CEF
= 180° - 60° - 86°
= 34° (Angles sum of triangle)
Answer(s): (a) 30°; (b) 34°