check the picture below, notice the distance from the focus to the directrix
bear in mind that, the vertex is a distance "p" from the focus point and a distance "p" from the directrix, that simply means, the vertex is half-way between both of those fellows
in this case, the focus point is above the directrix, that means, the parabola is vertical and opens upwards, "p" is a positive number for the focus/point form
[tex]\bf \textit{parabola vertex form with focus point distance}\\\\
\begin{array}{llll}
(x-{{ h}})^2=4{{ p}}(y-{{ k}}) \\
\end{array}
\qquad
\begin{array}{llll}
vertex\ ({{ h}},{{ k}})\\\\
{{ p}}=\textit{distance from vertex to }\\
\qquad \textit{ focus or directrix}
\end{array}[/tex]
so.. check the graph, you know what h,k are, and p, so, plug them in
