PSLE Lynn has a triangular piece of paper RST with SR = ST, ∠RST = 84° and ∠TUU = 67°. RUT and SUT are straight lines. She folded it along the line UV as shown.
- Find ∠w.
- Find ∠x.
(a)
Length of RS = Length of ST
Triangle RST is an isosceles triangle.
∠STR
= (180° - 84°) ÷ 2
= 96° ÷ 2
= 48° (Isosceles triangle)
∠w
= 180° - 67° - 48°
= 65° (Angles sum of triangle)
(b)
∠SRT = ∠STR = 48°
∠y
= 180° - 67° - 67°
= 46° (Angles on a straight line)
∠x
= 180° - 48° - 46°
= 86° (Angles sum of triangle)
Answer(s): (a) 65°; (b) 86°