# Vertices, Edges and Faces A vertex is a corner.
An edge is a line segment between faces.
A face is a single flat surface
.

Let us look more closely at each of those:

## Vertices A vertex (plural: vertices) is a point where two or more line segments meet.

It is a Corner.

This tetrahedron has 4 vertices.

 And this pentagon has 5 vertices: ## Edges This Pentagon
Has 5 Edges

For a polygon an edge is a line segment on the boundary joining one vertex (corner point) to another. This Tetrahedron
Has 6 Edges

For a polyhedron an edge is a line segment where two faces meet.

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

## Sides

"Side" is not a very accurate word, because it can mean: • An edge of a polygon, or
• A face of a polyhedron

## 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 = 2 (To find out more about this read Euler's Formula.)