PSLE Sabrina has a triangular piece of paper NPQ with PN = PQ, ∠NPQ = 76° and ∠QRR = 73°. NRQ and PRQ are straight lines. She folded it along the line RS as shown.
- Find ∠t.
- Find ∠u.
(a)
Length of NP = Length of PQ
Triangle NPQ is an isosceles triangle.
∠PQN
= (180° - 76°) ÷ 2
= 104° ÷ 2
= 52° (Isosceles triangle)
∠t
= 180° - 73° - 52°
= 55° (Angles sum of triangle)
(b)
∠PNQ = ∠PQN = 52°
∠v
= 180° - 73° - 73°
= 34° (Angles on a straight line)
∠u
= 180° - 52° - 34°
= 94° (Angles sum of triangle)
Answer(s): (a) 55°; (b) 94°