PSLE BCDE and CEFG are rhombuses. DHE is a straight line.
- Find ∠ECH.
- Find ∠DEF.
(a)
∠CED
= (180° - 110°) ÷2
= 70° ÷ 2
= 35° (Isosceles triangle)
∠ECH
= 180° - 128° - 35°
= 17° (Angles sum of triangle)
(b)
∠CGF
= 360° - 298°
= 62° (Angles at a point)
∠CEF = ∠CGF = 62° (Rhombus)
∠DEF
= 62° - 35°
= 27°
Answer(s): (a) 17°; (b) 27°