PSLE ABCD and BDEF are rhombuses. CGD is a straight line.
- Find ∠DBG.
- Find ∠CDE.
(a)
∠BDC
= (180° - 106°) ÷2
= 74° ÷ 2
= 37° (Isosceles triangle)
∠DBG
= 180° - 123° - 37°
= 20° (Angles sum of triangle)
(b)
∠BFE
= 360° - 291°
= 69° (Angles at a point)
∠BDE = ∠BFE = 69° (Rhombus)
∠CDE
= 69° - 37°
= 32°
Answer(s): (a) 20°; (b) 32°