3. fill in the blanks with center, circle, directrix, focus, line, parabola, or radius. a is the set of all points that are equidistant from two points. a is the set of all points that are equidistant from a given point. the given point is called the the segment showing the distance is called the a is the set of all points equidistant from a single point and a single line. the single point is called the and the single line is called theme