Finding the intersection of 3D segments

[xbeanx]

Hi guys.. I'm having trouble trying to find the intersection point of two line segments. I found a webpage:

http://mathforum.org/library/drmath/view/62814.html

that seems helpful, but the last bit is hard to understand. Particularly, the part that says "Once we have checked this, we can solve for 'a' by taking the magnitude of each side and dividing".

Anyway, can anyone help me figure this out?? My line segments are specified in point form (p1x, p1y)(p2x, p2y).

I tried searching on google but not nothing helpful (except for that webpage mentioned earlier).

[Moni]

Once I mentioned:

http://cm.bell-labs.com/who/clarkson/cis677/lecture/3/

In this thread:

http://online-judge.uva.es/board/viewtopic.php?t=2598

Hope it helps