  Speakman and Lee (2017) gave a formula for the volume of the convex hull of
the graph of a trilinear monomial, $y=x_1x_2x_3$, over a box in the nonnegative
orthant, in terms of the upper and lower bounds on the variables. This was done
in the context of using volume as a measure for comparing alternative
convexifications to guide the implementation of spatial branch-and-bound for
mixed integer nonlinear optimization problems. Here, we introduce an
alternative method for computing this volume, making use of the rich theory of
mixed volumes. This new method may lead to a natural approach for considering
extensions of the problem.
