# Measure and Classify Angles

You can use a protractor to measure the angle at the right. A protractor is a tool for measuring the size of the opening of an angle. The unit used to measure an angle is a degree.

A protractor has a center point at the bottom where two lines form right angles. To the right of this is the 0° mark. To the left is the 180° mark.

Find out more about measuring and classifying angles by reading the explanation below.