Degrees (Angles)

We can measure Angles in Degrees.

There are 360 degrees in one Full Rotation (one complete circle around).

(Angles can also be measured in Radians)

(Note: "Degrees" can also mean Temperature, but here we are talking about Angles)

The Degree Symbol: °

We use a little circle ° following the number to mean degrees.

For example 90° means 90 degrees

One Degree

This is how large 1 Degree is

The Full Circle

A Full Circle is 360°

Half a circle is 180°
(called a Straight Angle)

Quarter of a circle is 90°
(called a Right Angle)

Why 360 degrees? Probably because old calendars (such as the Persian Calendar) used 360 days for a year - when they watched the stars they saw them revolve around the North Star one degree per day.

Measuring Degrees

We often measure degrees using a protractor:

The normal protractor measures 0° to 180°

You can also get full-circle protractors.

But they are not as commonly used because they are a bit big and don't do anything special.