What did I do wrong?

No.11455625 ViewReplyOriginalReport
Please help. Saw this shit posted a different board, and got too invested trying to figure out a generic solution for any x and y. Haven't done any actual math in three years, so I am fucking rusty as fuck. Please send help, because I might be retarded. Could you also point out where I made the mistake? Right now I'm just trying to figure out a generic height equation for when the water stays in the form of a triangle.