The surface p = p0 consists of all points whose distance p from the origin is p0. Assuming p0 to be nonnegative, this is a sphere of radius p0 centered at the origin. 0 As in cylindrical coordinates, the surface 6 = 00 is a half-plane attached along the z-axis, making an angle of 90 with the positive x-axis. 0 The surface (13 = (130 consists of all points from which a line segment to the origin makes an angle of (130 with the positive z-axis. If 0