PSLE ABCD and BDEF are rhombuses. CGD is a straight line.
- Find ∠DBG.
- Find ∠CDE.
(a)
∠BDC
= (180° - 104°) ÷2
= 76° ÷ 2
= 38° (Isosceles triangle)
∠DBG
= 180° - 129° - 38°
= 13° (Angles sum of triangle)
(b)
∠BFE
= 360° - 287°
= 73° (Angles at a point)
∠BDE = ∠BFE = 73° (Rhombus)
∠CDE
= 73° - 38°
= 35°
Answer(s): (a) 13°; (b) 35°