PSLE Gem has a triangular piece of paper STU with TS = TU, ∠STU = 84° and ∠UVV = 69°. SVU and TVU are straight lines. She folded it along the line VW as shown.
- Find ∠x.
- Find ∠y.
(a)
Length of ST = Length of TU
Triangle STU is an isosceles triangle.
∠TUS
= (180° - 84°) ÷ 2
= 96° ÷ 2
= 48° (Isosceles triangle)
∠x
= 180° - 69° - 48°
= 63° (Angles sum of triangle)
(b)
∠TSU = ∠TUS = 48°
∠z
= 180° - 69° - 69°
= 42° (Angles on a straight line)
∠y
= 180° - 48° - 42°
= 90° (Angles sum of triangle)
Answer(s): (a) 63°; (b) 90°