## Euler's formula for polyhedraThe earliest known equation in topology. If F is the number of faces of a polyhedron,
E the number of edges, and V the number of vertices,
Euler's formula can be written asF - E + V = 2.
For example, the surface of a cube has six (square) faces, twelve edges, and eight vertices and, sure enough, 6 - 12 + 8 = 2. The quantity F - E + V is known as the
Euler characteristic. ## Related category• SOLIDS AND SURFACES | |||||

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