PSLE In the figure, STV and XWV are straight lines and WT is parallel to VU. ∠WXS is a right angle, ∠XST = 55°, ∠STU = 121° and ∠VWT = 72°.
- Find ∠STW.
- Find ∠TUV.
(a)
∠SVX
= 180° - 90° - 55°
= 35° (Angles sum of triangle)
∠VTW
= 180° - 72° - 35°
= 73° (Angles sum of triangle)
∠STW
= 180° - 73°
= 121° (Angles on a straight line)
(b)
∠VTU
= 360° - 121° - 73° - 121°
= 45° (Angles at a point)
∠TUV
= 180° - 45° - 45°
= 90°
Answer(s): (a) 121°; (b) 90°