# Another Parabola Theorem!

- Author:
- Tim Brzezinski

In the applet below, a parabola is shown.

**F = the focus of this parabola. d = the directrix of this parabola. V = the vertex of this parabola.****P = a point that lies ON the parabola.**(Feel free to move these points anywhere you'd like at any time.)**Note:****Segment***t*(that will soon appear) is tangent to the parabola at**point***P***.**How can you formally prove what this applet informally illustrates?