# Naming Conventions

The below video covers the written tutorial below - how to name angles based on their size and location.

## Naming Angles

Angles can be classified or described based on their size, as well as position relative to a shape. Both of these conventions are covered below.

## Naming Angles based on Size

Any angle that is less than 90 degrees is called an *acute* angle. *Right angles* are also known as *normal* angles; and they always measure exactly 90 degrees. An *obtuse angle* is any angle between 91 degrees and 180 degrees. A *reflex angle* refers to any angle between 181 degrees and 359 degrees. Knowing this, name the below angles (then *roll your mouse over the image* to see if you got them right).

Most angles are denoted by a curve, however right angles are usually always marked with a square. This is because all of the angles in a square are 90 degrees.

## Naming Angles based on Location

The angles in a shape can be measured either *internal* to the shape, or *external* to it. For example, the internal angles of a square are 90 degrees each, however the external angles are 270 degrees each.

It's possible to also have internal and external angles without shapes. Traditionally the *smaller* of the two angles is called the *internal* angle, and the *larger* is called the *external* angle.