PSLE Vanessa has a triangular piece of paper STU with TS = TU, ∠STU = 80° and ∠UVV = 67°. 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° - 80°) ÷ 2
= 100° ÷ 2
= 50° (Isosceles triangle)
∠x
= 180° - 67° - 50°
= 63° (Angles sum of triangle)
(b)
∠TSU = ∠TUS = 50°
∠z
= 180° - 67° - 67°
= 46° (Angles on a straight line)
∠y
= 180° - 50° - 46°
= 84° (Angles sum of triangle)
Answer(s): (a) 63°; (b) 84°