In the figure, GH = GK, ∠HGK = 31° and ∠LJK = 17°. Find
- ∠b
- ∠c
(a)
∠GHK
= (180° - 31°) ÷ 2
= 74.5° (Isosceles triangle)
∠b
= 180° - 17° - 74.5°
= 88.5° (Angles sum of triangle)
(b)
∠GKJ
= 180° - 74.5°
= 105.5° (Angles on a straight line)
∠c
= 17° + 105.5°
= 122.5° (Exterior angle of a triangle)
Answer(s): (a) 88.5°; (b) 122.5°