PSLE Xandra has a triangular piece of paper STU with TS = TU, ∠STU = 80° and ∠UVV = 73°. 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° - 73° - 50°
= 57° (Angles sum of triangle)
(b)
∠TSU = ∠TUS = 50°
∠z
= 180° - 73° - 73°
= 34° (Angles on a straight line)
∠y
= 180° - 50° - 34°
= 96° (Angles sum of triangle)
Answer(s): (a) 57°; (b) 96°