Question

I am trying to help my step son who missed half of physics class due to a funeral.

A laser beam is being shot through two different materials that have been stuck together. if theta 1 = 65.5 and theta 2 = 49.8 what is the index of refraction? (I got 1.2 which is correct) but cant get part 2

PART 2~ If the index of refraction of n3 is 3.6, what is the final angle of transmitting light theta 3?

THANKS IN ADVANCE FOR ANY HELP!
Chad on behalf of Zach ;)