1. The problem statement, all variables and given/known data Recall that in hyperbolic geometry the interior angle sum for any triangle is less than 180◦. Using this fact prove that it is impossible to have a rectangle in hyperbolic geometry. 2. Relevant equations 3. The attempt at a solution - I wanted to use the idea that rectangles are 4 right angles meaning they would add up to 360 to help with the proof. I am not sure if that is useful, or even how I would write that in a proof.