Vertices, Edges and Faces
A vertex is a corner.
An edge is a line segment that joins two vertices.
A face is an individual surface.
Let us look more closely at each of those:
A vertex (plural: vertices) is a point where two or more straight lines meet.
It is a Corner.
This tetrahedron has 4 vertices.
|And this pentagon has 5 vertices:|
An edge is a line segment that join two vertices ...
... where two faces meet on a polyhedron
(this tetrahedron has 6 edges),
... or on the boundary of a polygon
(this pentagon has 5 edges)
A polygon's edges are sometimes called sides.
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)
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,
6 + 8 − 12 = 2
(To find out more about this read Euler's Formula.)