Focus and Directrix Exploration

How does the distance between the vertex and the focus compare to the distance between the vertex and the directrix? Change the values for a, h, and k. Is that always the case?

Which parameter - a, h, or k - changes the distance of the focus and the directrix from the parabola?

What happens to the focus and the directrix as "a" gets further away from 0? What happens to them as "a" gets closer to 0?

How do "h" and "k" change the focus and the directrix?

What does "c" represent on the graph of a parabola? Be sure to change the values of "h" and "k" to make sure you're correct?