How do I project a point on to a plane?

I have a point inside of a right cylinder. I want to project that point to the plane that is one of the 'caps'. I know only the coordinate for the point, the radius and height of the cylinder, and the points of its two caps.How do I project a point on to a plane?Are the 'caps' parallel to one of the coordinate planes?



E.g. if the cylinder's axis of symmetry is parallel to the z-axis (assuming it's a circular cylinder :), then it's caps have the form z=C for some constant C.



Then the point (x_0, y_0, z_0) projected onto this plane is (x_0, y_0, C).