Question

which defines a circle?
two rays with a common endpoint
a piece of a line with two endpoints
a piece of a line with one endpoint
all coplanar points equidistant from a given point

Explanation:

• Analyze the first option: "two rays with a common endpoint" defines an angle, not a circle.
• Analyze the second option: "a piece of a line with two endpoints" is a segment, not a circle.
• Analyze the third option: "a piece of a line with one endpoint" is a ray, not a circle.
• Analyze the fourth option: By the definition of a circle, a circle is the set of all coplanar points that are equidistant from a given point (the center).

Answer:

D. all coplanar points equidistant from a given point