Using the equation of an parabola, it is found that the value of p is 0.5.
The equation of a parabola that is concave to the left or to the right, that is, that has directrix y = k, and vertex (h,k), is given by:
[tex](y - k)^2 = 4p(x - h)[/tex]
The focus is at: (h, k + p).
The directrix is at: y = k - p
For this problem, we have that:
Since [tex]k = 3 - p[/tex]:
[tex]3 - p - p = 4[/tex]
[tex]2p = 1[/tex]
[tex]p = \frac{1}{2}[/tex]
[tex]p = 0.5[/tex]
The value of p is 0.5.
A similar problem is given at https://brainly.com/question/17987697
