PSLE Sabrina has a triangular piece of paper QRS with RQ = RS, ∠QRS = 80° and ∠STT = 66°. QTS and RTS are straight lines. She folded it along the line TU as shown.
- Find ∠v.
- Find ∠w.
(a)
Length of QR = Length of RS
Triangle QRS is an isosceles triangle.
∠RSQ
= (180° - 80°) ÷ 2
= 100° ÷ 2
= 50° (Isosceles triangle)
∠v
= 180° - 66° - 50°
= 64° (Angles sum of triangle)
(b)
∠RQS = ∠RSQ = 50°
∠x
= 180° - 66° - 66°
= 48° (Angles on a straight line)
∠w
= 180° - 50° - 48°
= 82° (Angles sum of triangle)
Answer(s): (a) 64°; (b) 82°