Question

question 24 of 25
what is the name of the line that you use to define a parabola?
a. perpendicular
b. focus
c. directrix
d. parallel

Explanation:

A parabola is defined as the set of all points equidistant from a fixed point (the focus) and a fixed line (the directrix). So the line used to define a parabola is called the directrix.

Answer:

C. Directrix