Question

which of these is the best definition of a circle?
a. the set of all points in a plane for which the sum of the distances to two fixed points equals a certain constant
b. the set of all points in a plane that are a certain distance from a single point
c. the set of all points in a plane for which the difference between the distances to two fixed points equals a certain constant
d. the set of all points in a plane that are equidistant from a point and a line

Explanation:

A circle is defined as the set of all points in a plane that are at a fixed distance (radius) from a single - point (center). Option A describes an ellipse, option C describes a hyperbola, and option D describes a parabola.

Answer:

B. The set of all points in a plane that are a certain distance from a single point