PSLE Esther has a triangular piece of paper GHJ with HG = HJ, ∠GHJ = 82° and ∠JKK = 67°. GKJ and HKJ are straight lines. She folded it along the line KL as shown.
- Find ∠m.
- Find ∠n.
(a)
Length of GH = Length of HJ
Triangle GHJ is an isosceles triangle.
∠HJG
= (180° - 82°) ÷ 2
= 98° ÷ 2
= 49° (Isosceles triangle)
∠m
= 180° - 67° - 49°
= 64° (Angles sum of triangle)
(b)
∠HGJ = ∠HJG = 49°
∠p
= 180° - 67° - 67°
= 46° (Angles on a straight line)
∠n
= 180° - 49° - 46°
= 85° (Angles sum of triangle)
Answer(s): (a) 64°; (b) 85°