# Naming Angle Components

The below video refers to the written content both for this tutorial (below) and the last one. We hope you enjoy it!

Before we learn the names for different types of angles, lets first learn what the different components of an angle are, and how to refer to specific angles when there are more than one, for example in a polygon.

## What are arms and vertices?

When two lines intersect, they form an angle. The two lines are referred to as *arms*, and the point of intersection is the *vertex* (*roll over the image below to see*). *Vertices* is the plural for vertex.

These terms are not restricted for use in maths - they're used to describe the highest points of everyday items, including the summits of mountains.

## Which angle?

When more than two lines come together, there are multiple intersection points. Each intersection is referred to by the names of the lines that create it. The angle or vertex of interest is always in the middle (*as below*). Note that the other letters are always in either clockwise or anticlockwise direction (either way is fine, so long as you're consistent).