I'm not sure if this falls under calculus as its been a while since I took it.

I'm writing a program and I need help with finding projectile parabola equations.

Rather than explain the whole situation I drew a quick, but poor, picture in paint.net.

http://www.mathhelpforum.com/math-he...1&d=1263622842

Basically I need know, that given x1,y1,x2,y2, and y0, can I find x0.

I already solved another situation where x0,y0 is known but another point is missing. I just cannot seem to do it when the center point x-value is not known.

It seems like it should be simple, but maybe I'm just tired. I could use some help please.