Wave refraction in geological layers with Snell's law

[LukasNZ]

Ok so I am completely lost for this question =/ It's a 5 page paper and this is answer is needed to complete several others.

Homework Statement

A Thumper Truck sends a wave pulse traveling at a speed of 1800 ms-1 through Geological Layer 1.
Using the data from the diagram below calculate the speed of the wave in Geological layer 2.

Homework Equations

The diagram shows two mediums (geological layer 1 and 2) with the normal line going through them at a right angle. The wave at its point when it goes through layer 1 is at 37 degrees to the normal and when it reaches layer 2 it decreases to 15 degrees to the normal. Does this mean that layer 2 is denser? and if so in what equation would you use the angles given and the speed to determine the speed of the wave pulse in layer 2?

Thanks =]

The Attempt at a Solution

 

[Doc Al]

Look up Snell's law of refraction, which describes how waves bend when passing into a medium with a different wave speed.