The distance from the vertex to the focus is p.
In this case, p = 1. This parabola is centered at the origin also known as the point (0,0). In other words, (h, k) = (0, 0).
The general equation for a parabola is
(x - h)^2 = 4p(y - k).
P = 1
h = 0
k = 0
We now plug and chug.
(x - 0)^2 = 4(1)(y - 0)
x^2 = 4y
Done.
P. S. I decided to include a picture of the graph of this parabola.
