Degree in Angles: Definition, Symbol, Examples, Chart, and Practice

What is a degree in geometry?

A degree is a unit for measuring an angle.

It tells how wide an angle opens or how far something turns.

The degree symbol is °. So 45 degrees is written as 45°.

When you need to find the number yourself, use a protractor. The lesson on measuring angles with a protractor shows the steps.

Degree rule

Use degrees when you want to name the size of an angle.

A bigger degree number means a wider angle or a bigger turn.

A 20° angle is small. A 90° angle is a square corner. A 180° angle is a straight angle.

Common degree examples

These degree measures appear often in angle lessons.

You can use them as landmarks when deciding if an angle is small, square, straight, or a full turn.

For a wider list of names, review types of angles after this lesson.

How to read a degree label

Read the number first, then say degrees.

For example, 35° is read as 35 degrees.

For right angles, the label is 90° because a square corner measures 90 degrees.

Worked example

Problem: An angle is labeled 120°. Is it smaller or larger than a right angle?

Step 1: A right angle is 90°.

Step 2: Compare 120° with 90°.

Step 3: 120 is greater than 90.

Answer: A 120° angle is larger than a right angle.

Degrees and turns

Degrees also help describe turns.

A half turn is 180°. A full turn is 360°.

A reflex angle is more than 180° and less than 360°.

Common mistakes

Do not forget the degree symbol after the number.

Do not say a larger drawing always has a larger degree measure. The angle opening is what matters.

Do not mix up 180° and 360°. 180° is a straight angle, and 360° is a full turn.

Quick practice

1. 45° is read as 45 degrees.

2. 90° is the measure of a right angle.

3. 180° is a straight angle.

4. 360° is one full turn.