# Vertices, Edges and Faces

A vertex is a corner.

An edge joins one vertex with another.

A face is an individual surface.

Let us look more closely at each of those:

## Vertices

A It is a Corner. This tetrahedron has 4 vertices. |

And this pentagon has 5 vertices |

## Edges

An edge is a line segment that joins two vertices. This tetrahedron has 6 edges. And this pentagon has 5 edges |

It can also be the boundary of a shape. Such as the circumference of a circle. |

## Faces

A face is any of the individual surfaces of a solid object. This tetrahedron has 4 faces (there is one face you can't see) |

## Euler's Formula

**For many solid shapes the**

**Number of Faces**- plus the
**Number of Vertices** - minus the
**Number of Edges**

**always equals 2**

This can be written: **F + V - E = 2**

Try it on the cube: A cube has 6 Faces, 8 Vertices, and 12 Edges, so: 6 + 8 - 12 = (To find out more about this read Euler's Formula.) |