PSLE Emma has a triangular piece of paper LMN with ML = MN, ∠LMN = 76° and ∠NPP = 70°. LPN and MPN are straight lines. She folded it along the line PQ as shown.
- Find ∠r.
- Find ∠s.
(a)
Length of LM = Length of MN
Triangle LMN is an isosceles triangle.
∠MNL
= (180° - 76°) ÷ 2
= 104° ÷ 2
= 52° (Isosceles triangle)
∠r
= 180° - 70° - 52°
= 58° (Angles sum of triangle)
(b)
∠MLN = ∠MNL = 52°
∠t
= 180° - 70° - 70°
= 40° (Angles on a straight line)
∠s
= 180° - 52° - 40°
= 88° (Angles sum of triangle)
Answer(s): (a) 58°; (b) 88°