PSLE DEFG is a rhombus. GJE and GHFK are straight lines.
- Find ∠DEG.
- Find ∠GFK.
- Find ∠GJH.
(a)
∠DEG
= (180° - 100°) ÷ 2
= 40° (Isosceles triangle)
(b)
∠EFG
= ∠EDG
= 100° (Rhombus)
∠GFK
= 180° - 100°
= 80° (Angles on a straight line)
(c)
∠HEJ
= ∠DEJ
= 40° (Rhombus)
∠EHJ
= 180° - 71°
= 109° (Angles on a straight line)
∠GJH
= 40° + 109°
= 149° (Exterior angle of a triangle)
Answer(s): (a) 40° (b) 80° (c) 149°