It is a common knowledge that the sum of the angles forming straight line is equal to 180°.
180 = ∠WSV + ∠USV
We are given that ∠WSV is 162°, by difference we get ∠USV to be equal to 18°. Also, ∠USV and ∠RSW are vertical angles (which means that they share common vertex and their extended sides forms a straight line with each other), their measures should be equal. Thus, ∠RSW is also 18°. However, with the available information, we cannot for sure say that ∠UST is 18°.
