An angle is formed by two rays sharing an endpoint called the vertex. An angle is named with the vertex letter followed by a number or letters for points on each ray, with the vertex in the middle. There are four types of angles based on degree measure: less than 90 degrees, exactly 90 degrees, more than 90 degrees but less than 180 degrees, and exactly 180 degrees.

2. 1
 An Angle is formed by two rays with the same
endpoint.
 The rays are the sides of the angle (ex. BA
and BC)
 The endpoint is the vertex of the angle (ex. B)

3. 1
 You can name an angle by:
 The vertex B
 A Number 1
 A point on each ray and the vertex, ABC
or CBA
▪ When naming an angle by three
points the vertex must go in the
middle.

7. Less than 90
degrees
Exactly 90
degrees More than 90
degrees
Exactly 180
degrees