Home » Blog » Equation of the day Polyhedral formula Whose equation is this? AnswerLeonhard Euler The above equation is known as Euler‘s polyhedron formula. It corresponds to the Euler characteristic of the sphere (i.e. χ = 2), and applies identically to spherical polyhedra. You can see various proofs of this formula here.Leonhard Euler The above equation is known as Euler‘s polyhedron formula. It corresponds to the Euler characteristic of the sphere (i.e. χ = 2), and applies identically to spherical polyhedra. You can see various proofs of this formula here. Share this