Question

the set of points indicated by 12. is the _____ of the angle. diagram: two rays forming an angle, labeled 10 (rays), 11 (interior), 12 (common endpoint). options: vertex (selected), exterior, interior

Explanation:

An angle is formed by two rays (the sides, labeled 10 here) that share a common endpoint. This common endpoint is called the vertex of the angle. The point labeled 12 is where the two sides of the angle meet, so it is the vertex. The "exterior" is the area outside the angle, and the "interior" is the area between the two sides, which doesn't match point 12's position.

Answer:

A. vertex