1. The problem statement, all variables and given/known data A concave shaving mirror has a radius of curvature of 40 cm. It is positioned so that the (upright) image of a man's face is 3.30 times the size of the face. How far is the mirror from the face? 2. Relevant equations M = Si/S 1/S + 1/Si = 2/R 3. The attempt at a solution I have 2 equations with 2 unknowns. I isolated Si in the first one and substituted this expression into equation 2 to find S. I get an answer of 26.1cm. The computer keeps telling me I'm wrong though. Could someone check my math or tell me if my equation setup is correct?