# Types of Angles (Mathematics Lesson)

# Types of Angles

Angles can be classified as acute, right, obtuse, straight, reflex or full.# Acute Angles

An acute angle is an angle of less than 90°.Read more about acute angles

# Right Angles

A right angle is an angle of 90°.(

**Note:**Right angles are often denoted by adding a small right angle that forms a square with the angle.)

Read more about right angles

# Obtuse Angles

An obtuse angle is an angle greater than 90° and less than 180°.Read more about obtuse angles

# Straight Angles

A straight angle is an angle of 180°.Read more about straight angles

# Reflex Angles

A reflex angle is an angle greater then 180° and less than 360°.Read more about reflex angles

# Full Angles

A full angle is an angle of 360°.Read more about full angles

##### Curriculum

##### Interactive Test

**show**

##### Note

**WHAT IS AN ANGLE?**

An angle is created by two rays that have a common end point, called the vertex.

**WHO CLASSIFIED ANGLES?**

Euclid classified angles in his book,

*Elements*.

**Definition 10:**"When a straight line standing on a straight line makes the adjacent angles equal to one another, each of the equal angles is right".

**Definition 11:**"An obtuse angle is an angle greater than a right angle".

**Definition 12:**"An acute angle is an angle less than a right angle".