The common endpoint of the two rays of an angle is called the:

1. The two rays are the sides of the angle. 2. The point where they join has its own name. 3. The endpoint is called the vertex of the angle. 4. So the answer is the vertex. _Source: OpenStax 'Algebra and Trigonometry 2e', Ch 7 'The Unit Circle: Sine and Cosine Functions'_