The line of symmetry.
It divides the parabola into to halves that are exactly the same.
Answer: 8cm
Step-by-step explanation:

Solve for h;



Answer:
11.25
Step-by-step explanation:
The equation for a parabola is:
y − k = 1/(4p) (x − h)²
where (h, k) is the vertex and p is the distance from the focus to the vertex.
1/(4p) = 1/45
4p = 45
p = 11.25
The distance from the vertex to the focus is 11.25 inches.
Answer:
r=4
Step-by-step explanation:
15r-6r=36
9r=36
r=36/9
r=4