Question

which is defined using the undefined terms point and line?
○ angle
○ circle
○ parallel lines
○ ray

Explanation:

• An angle is formed by two rays (or lines) with a common endpoint (point), but its definition also involves the concept of rotation or the space between the rays, not just point and line directly.
• A circle is defined as the set of all points in a plane equidistant from a given point (center), so it relies on the concept of a point and distance, not just point and line.
• Parallel lines are lines in a plane that do not intersect, but their definition is about the relationship between two lines, and it also involves the plane concept implicitly, not just point and line.
• A ray is defined as a part of a line that starts at a point (endpoint) and extends infinitely in one direction. So it uses the undefined terms "point" (the endpoint) and "line" (the infinite straight path) to be defined.

Answer:

D. ray