# What Is a Straight Angle? (Mathematics Lesson)

# What Is a Straight Angle?

An straight angle is an angle of 180°.# Real Examples of Straight Angles

The angles below are all straight angles:# Supplementary Angles

Two angles are supplementary if they add up to a straight angle.Read more about supplementary angles

##### Curriculum

##### Interactive Test

**show**

##### Note

**WHAT'S IN A NAME?**

A straight angle is called straight because it forms a straight line.

# DO A 180

A straight angle is half a revolution, it changes the direction to point the other way.The phrases "do a 180", "a complete 180" refers to someone who completely changes their mind or direction the other way.