Even in two dimensions, the analogous fact about triangles is not obvious to me. Jim On Sunday, November 6, 2016, Bill Gosper <billgosper@gmail.com> wrote:

but is it obvious why the center of mass of such a simplex is the center of mass of unit masses at its vertices? --rwg _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com <javascript:;> https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun