PSLE Tammy has a triangular piece of paper RST with SR = ST, ∠RST = 82° and ∠TUU = 69°. 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° - 82°) ÷ 2
= 98° ÷ 2
= 49° (Isosceles triangle)
∠w
= 180° - 69° - 49°
= 62° (Angles sum of triangle)
(b)
∠SRT = ∠STR = 49°
∠y
= 180° - 69° - 69°
= 42° (Angles on a straight line)
∠x
= 180° - 49° - 42°
= 89° (Angles sum of triangle)
Answer(s): (a) 62°; (b) 89°