Question

the definition of a circle uses the undefined term

arc

line

plane

ray

Explanation:

A circle is defined as the set of all points in a plane that are at a given distance from a given point. The term "plane" is an undefined term in geometry. An arc is a part of a circle (a defined term). A line is a one - dimensional figure (not directly used in the basic definition of a circle). A ray is a part of a line (also not the key undefined term for a circle's definition).

Answer:

plane