This is College Physics Answers with Shaun Dychko. Brewster's angle is the angle at which incident light will be reflected, polarized from a material. And so it's the ratio of the index refraction of the material that it's bouncing off of divided by the index refraction of the initial material that it’s traveling through. and that's going to be the tangent of Brewster's angle. So, we take the inverse tangent on both sides here to solve for the angle. So, the inverse tangent of <i>n two</i> over <i>n one</i>. So, we have the inverse tangent of index of refraction of water which is the second material that it's the light is bouncing off of divided by the index of refraction of the initial material which is air that has an index refraction of 1.0. This gives an angle of 53.1 degrees.