Cylindrical co-ordinate system

In the cylindrical co-ordinate system the co-ordinate of any point is given by three components r, theta, and z. The co-ordinates r and theta represent polar co-ordinates of a point in xy plane. And the z co-ordinate is a distance of the defined point from xy plane.

Thus the ordinate along x, y, and z axis are respectively:

x = r × cos (theta),

y = r × sin (theta),

z = z.