What is the three point notation? Solution In a 3D Cartesian coordinate system, a point P is referred to by three real numbers (coordinates), indicating the positions of the perpendicular projections from the point to three fixed, perpendicular, graduated lines, called the x,y,z axes respectively which intersect at the origin. Any point P can be denoted as P(x,y,z) , where x,y,z are the perpendicular distance of point P from x,y,z axis respectively. The way of representing the point in 3D co-ordinate is done by three point notation..