Answer:
9
Step-by-step explanation:
Let the equation of a parabola be
[tex]y^{2}[/tex] = 4ax.
Then , focal length of the parabola is a.
As , (0,0) is the vertex and its focus is (a,0)
Thus, focal length comes out to be a.
Here,
a is given as 9 units .
Thus focal length of the parabola, d, equals to 9 units
