# Question about the refraction of light in a swimming pool

Here is a homework question that I'm having a hard time understanding:

Out of pure intellectual curiosity you have donned a snorkeling face mask and allowed yourself to sink to the bottom of the pool, face-up. If where you are lying the pool is 2.50 m deep, what is the diameter of the circle (in meters) in which you see your friends scurrying about at the edge of the pool trying to figure out what you have done to yourself this time? The index of refraction of water is 1.33.

I think the question should be approached using Snell's Law, but I'm struggling to find the angles needed to solve for anything. The following is a picture of my attempt, but again it seems useless without knowing the angles.

We have $n_1 = 1$, $n_2 = 1.33$, so

$$\begin{array} !\frac{\sin \theta_2}{\sin \theta_1} & = \frac{n_1}{n_2} \\ \sin \theta_2 &= \frac{n_1 \sin \theta_1}{n_2} \end{array}$$