Answer
$0.33^{\circ}$
Work Step by Step
We know that
$\theta_v=sin^{-1}\frac{n_{air}sin\theta_1}{n_{liq},v}$
We plug in the known values to obtain:
$\theta_v=sin^{-1}\frac{1.00 sin45^{\circ}}{1.332}=32.064^{\circ}$
similarly
$\theta_r=sin^{-1}\frac{n_{air}sin\theta_1}{n_{liq},r}$
We plug in the known values to obtain:
$\theta_r=sin^{-1}\frac{1.00 sin45^{\circ}}{1.330}=32.391^{\circ}$
Now $|\theta_v-\theta_r|=|32.064^{\circ}-32.391^{\circ}|=0.33^{\circ}$
