The figure is not drawn to scale. BDEF is a trapezium and BD // FE. Given that BF = BC, ∠FBC = 79° and ∠BDE = 103°.
- Find ∠DEF
- Find ∠BCF
- Find ∠CFE
(a)
∠DEF
= 180° - 103°
= 77° (Interior angles, BD//FE)
(b)
∠BCF
= (180° - 79°) ÷ 2
= 101° ÷ 2
= 50.5° (Isosceles triangle)
(c)
∠CFE
= ∠BCF
= 50.5° (Alternate angles, BD//FE)
Answer(s): (a) 77°; (b) 50.5°; (c) 50.5°