1. The problem statement, all variables and given/known data Find the minimum height of a vertical flat reflector, in which a 1,78 m person can see its full reflection. 2. Relevant equations M = h'/h 3. The attempt at a solution I really don't know what to do here, and I feel as if I'm missing some crucial element. The chapter about vertical reflectors is very small (3 pages or so) and really has no other exercises besides a theoretical one based on this design: I tried going at it by creating "formulas" with the different angles, but nothing really worked. I assume the hidden detail is in that the person can see its full reflection, but other than h = h', I'm not saying anything else. It might be an issue in translation as well. Any help is appreciated!