PSLE BCDE and CEFG are rhombuses. DHE is a straight line.
- Find ∠ECH.
- Find ∠DEF.
(a)
∠CED
= (180° - 96°) ÷2
= 84° ÷ 2
= 42° (Isosceles triangle)
∠ECH
= 180° - 130° - 42°
= 8° (Angles sum of triangle)
(b)
∠CGF
= 360° - 278°
= 82° (Angles at a point)
∠CEF = ∠CGF = 82° (Rhombus)
∠DEF
= 82° - 42°
= 40°
Answer(s): (a) 8°; (b) 40°