Hello there I am trying to figure out this but am having some difficulty. Your help would be much appreciated. I have 3 points in 3D space: (x1,y1,z1), (x2,y2,z2) and (x3,y3,z3). My objective: I need to find out the radius of the circle that passes through these 3 points. I know how to do this if the points were in 2D space (there are several Google links that explain it). But I don't know how to do it if the points are in 3D space. I don't need the equation of the circle, just the radius of the circle that passes through these three 3D points. Thanks a lot for taking the time to respond.