Degree of an Angle

Term generally used to refer to the unit of measure of angles.

A degree is the measure of a central angle whose sides intercept an arc that is \(\dfrac{1}{360}\) of the circumference of a circle.

Symbols

The symbol for the measure of an angle in degrees (°) is placed immediately to the right of the number representing the measure.
The measure “35°” is read “35 degrees”.

A degree of an angle can be divided into 60 minutes.
The symbol for a minute of an angle (‘) is placed immediately to the right of the number representing the measure.
The measure “15’” is read “15 minutes”.

A minute of an angle can be divided into 60 seconds.
The symbol for a second of an angle (\(^{\prime \prime}\)) is placed immediately to the right of the number representing the measure.
The measure “28″” is read “28 seconds”.

Examples

A circle is divided into 360 degrees or 360°.
A right angle measures 90°.

Educational Note

The degree symbol was introduced by Greek mathematician, astronomer and geographer Claudius Ptolemy in his work, the Almagest. Ptolemy used a 360° circle to measure angles. The symbol is derived from the character for the Greek letter omicron.