  We consider the embedding of the Standard Model fields in a
$(4+d)$-dimensional theory while gravitons may propagate in $d'$ extra, compact
dimensions. We study the modification of strengths of the gravitational and
gauge interactions and, for various values of $d$ and $d'$, we determine the
energy scale at which these strengths are unified. Special cases where the
unification of strengths is characterized by the absence of any hierarchy
problem are also presented.
