Given three points P1(-2, 0, 3), P2(0, 4, -1), and P3(3, 1, 3) find the perpendicular distance from point P3 to the line joining P1 and P2.

I have two tools; the dot and cross product. But I'm not seeing how to use them to obtain the $\displaystyle \perp$ distance.

{answer on this side of wall}