1. The problem statement, all variables and given/known data I solved the problem, but upon further observation, I discovered that what I did didn't make sense. (these are rounded numbers, which shouldn't make a difference in my question) do = 13 cm (do is what I solved for in the problem, and according to the online system it was correct) f = 24 cm di = 33 cm (the man is facing a convex mirror with his image behind the mirror) 2. Relevant equations 1/f = 1/do + 1/di 3. The attempt at a solution Since this is a convex mirror, f and di should be negative. Yet, it doesn't make sense with those conventions. 1/f = 1/do + 1/di 1/do = 1/f - 1/di 1/do = (1/-24) - (1/-33) do = -88 cm, which means the object is behind the mirror and my methodology was inconsistent. Where is the issue? Is it just an inconsistency with sign conventions by them?