PSLE Wendy has a triangular piece of paper FGH with GF = GH, ∠FGH = 82° and ∠HJJ = 67°. FJH and GJH are straight lines. She folded it along the line JK as shown.
- Find ∠l.
- Find ∠m.
(a)
Length of FG = Length of GH
Triangle FGH is an isosceles triangle.
∠GHF
= (180° - 82°) ÷ 2
= 98° ÷ 2
= 49° (Isosceles triangle)
∠l
= 180° - 67° - 49°
= 64° (Angles sum of triangle)
(b)
∠GFH = ∠GHF = 49°
∠n
= 180° - 67° - 67°
= 46° (Angles on a straight line)
∠m
= 180° - 49° - 46°
= 85° (Angles sum of triangle)
Answer(s): (a) 64°; (b) 85°