1. The problem statement, all variables and given/known data Surface V: a dot x = 9 with a=(2,-3,6). Calculate the distance from O=(0,0,0) to V. 2. Relevant equations ? 3. The attempt at a solution The shortest distance is perpendicular to V. If n is the normalvector, n dot V = 0. I've got no clue from here. I think I need to find a proper equation for V, but I don't know how.