1. The problem statement, all variables and given/known data If a force f acts at a point x show that its moments about the three coordinate axes are the components of a vector, x x f. 2. Relevant equations Uh... Euclidean space R3 in cartesian system. x = <x1, x2, x3> f = <f1, f2, f3> 3. The attempt at a solution Okay, so far I have just taken the vector product. (x2f3-x3f2)e(1) + (x1f3-x3f1)e(2) + (x1f2-x2f1)e(3). This is where I have gotten and it shows the moments as components of the vector x x f. There has to be more though, this answer just seems to fall a bit short of a proof.