PSLE DEFG is a rhombus. GJE and GHFK are straight lines.
- Find ∠DEG.
- Find ∠GFK.
- Find ∠GJH.
(a)
∠DEG
= (180° - 102°) ÷ 2
= 39° (Isosceles triangle)
(b)
∠EFG
= ∠EDG
= 102° (Rhombus)
∠GFK
= 180° - 102°
= 78° (Angles on a straight line)
(c)
∠HEJ
= ∠DEJ
= 39° (Rhombus)
∠EHJ
= 180° - 63°
= 117° (Angles on a straight line)
∠GJH
= 39° + 117°
= 156° (Exterior angle of a triangle)
Answer(s): (a) 39° (b) 78° (c) 156°