PSLE BCDE and CEFG are rhombuses. DHE is a straight line.
- Find ∠ECH.
- Find ∠DEF.
(a)
∠CED
= (180° - 108°) ÷2
= 72° ÷ 2
= 36° (Isosceles triangle)
∠ECH
= 180° - 124° - 36°
= 20° (Angles sum of triangle)
(b)
∠CGF
= 360° - 283°
= 77° (Angles at a point)
∠CEF = ∠CGF = 77° (Rhombus)
∠DEF
= 77° - 36°
= 41°
Answer(s): (a) 20°; (b) 41°