Vocabulary Section 1-4

1

Angle, Side, Vertex

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)

1

Naming an Angle:

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.

Postulate 1-7: Protractor Postulate

Angle Measure

Congruent Angles

Types of AnglesLess than 90

degreesExactly 90

degrees More than 90 degrees

Exactly 180 degrees

Postulate 1-8: Angle Addition Postulate