Calculate the angle W R S, given that RW is a tangent to the circle at R and RS is the diameter.

Here are the calculations for the angles:

1.2.1 Calculate $\text{W}\hat{\text{R}}\text{S}$

Step 1: Identify the relationship between the tangent and the diameter.
RW is a tangent to the circle at R, and RS is the diameter. The angle between a tangent and a diameter at the point of contact is $90^\circ$.

$$\text{W}\hat{\text{R}}\text{S} = 90^\circ$$

The size of $\text{W}\hat{\text{R}}\text{S}$ is $\boxed{\text{90}^\circ}$.

**1.2.2 Calculate $\hat{\text{