A light ray enters a rectangular block of plastic at an

Question

Question: A light ray enters a rectangular block of plastic at an angle of θ1 = 45.0^o and emerges at an angle of θ2 = 76.0^o.

Part I: Determine the index of refraction for the plastic.

Part II: If the light ray enters the plastic at a point L = 50.0 cm from the bottom edge, how long does it take the light ray to travel through the plastic?

Please show work I think I have the answer just not positive.