Question

which is a property of an angle? has two sides that each extend forever in both directions has two endpoints has two center points has two rays that share a common endpoint

Explanation:

An angle is defined as two rays that share a common endpoint (the vertex). A line has no endpoints and extends forever in both directions. A line segment has two endpoints. There is no such thing as a "center point" for an angle in the context of its basic definition.

Answer:

has two rays that share a common endpoint