PSLE In the figure, BCE and GFE are straight lines and FC is parallel to ED. ∠FGB is a right angle, ∠GBC = 54°, ∠BCD = 110° and ∠EFC = 70°.
- Find ∠BCF.
- Find ∠CDE.
(a)
∠BEG
= 180° - 90° - 54°
= 36° (Angles sum of triangle)
∠ECF
= 180° - 70° - 36°
= 74° (Angles sum of triangle)
∠BCF
= 180° - 74°
= 110° (Angles on a straight line)
(b)
∠ECD
= 360° - 110° - 74° - 110°
= 66° (Angles at a point)
∠CDE
= 180° - 66° - 66°
= 48°
Answer(s): (a) 110°; (b) 48°