1. The problem statement, all variables and given/known data What surface is represented by r . a = conts. that is described if a is a vector of constant magnitude and direction from the origin and r is the position vector to the point P(x1, x2, x3) on the surface? 3. The attempt at a solution I know that the dot product of two vectors is a scalar. But I don't exactly understand what that scalar is a representation of. I don't necessarily want to have my homework question answered for me, I just don't know how I am supposed to approach it because I can't visualize what the scalar product is telling me (if there is any visualization possible).