People how to write a function of the distance between parallel lines in space?

Question

Geometry

Help, math finally doesn’t come in (Help there are 4 points, let's call them M, N, P, Q, - MN - forms one straight line, PQ - another, we know that the lines are parallel. How to find the distance between them, we know the coordinates of the points. Thanks.
UPD. Straight lines in space, like all points

Answer 1

Pi * (MN - PQ) / exp (-root of two)