I have no idea where to start on this one, I've been trying at it for 2 days now, and I just don't understand.

A ray of light is incident at 35.0° on a pane of glass with a thickness, t, of 5.00 mm and an index of refraction of n = 1.70. The rays entering the glass and leaving the glass are parallel, but the ray exiting the glass has been displaced. What is the displacement of the ray?

[Hints: Let the length of the ray in the glass be represented by x. Look for useful triangles involving d and t. The value of d is between 1.38 mm and 1.46 mm.]