1. The problem statement, all variables and given/known data A given surface contains all points G such that the distance from G to the plane z=4 is double the distance from point G to the pt. (2, -3, 1). Find eqn for the surface. 2. Relevant equations I thought the distance formula for a point to a plane would help, but I can tell that the equation is going to have to be that of a parabola. 3. The attempt at a solution I've made at least 5 unsuccessful attempts, and have NO idea where to go from here.