The Cayley-Menger determinant is a determinant that gives the volume of a simplex in j dimensions. If S is a j-simplex in R^n with vertices v_1, ..., v_(j + 1) and B = (β_(i k)) denotes the (j + 1)×(j + 1) matrix given by β_(i k) = left bracketing bar v_i - v_k right bracketing bar _2^2, then the content V_j is given by V_j^2(S) = (-1)^(j + 1)/(2^j (j!)^2) det(B^^),

Heron's formula | quadrilateral | tetrahedron

Arthur Cayley | Karl Menger