In the figure, FGJ is a triangle with GJ = GF, while EFGH is a parallelogram and HGJ is a straight line. Given ∠GHE = 100°, ∠DGJ = 142° and ∠EDG = 57°, find
- ∠GFJ
- ∠DGF
(a)
∠EHG
= ∠FGJ
= 100° (Corresponding angles)
∠GFJ
= (180° - 100°) ÷ 2
= 40° (Isosceles triangle)
(b)
∠DGF
= 360° - 142° - 100°
= 118° (Angles at a point)
Answer(s): (a) 40°; (b) 118°