Determine the missing side length: [asy] size(4cm); void mra(pair u, pair v, pair w, real r){ draw(v+(u-v)/length(u-v)*r--v+(u-v)/length(u-v)*r+(w-v)/length(w-v)*r--v+(w-v)/length(w-v)*r); } pair k=(0,0); pair l=(3,sqrt(3)); pair n=(3,0); label(rotate(30)*"$2\sqrt 3$",(k+l)/2,NW); label("$\sqrt 3$",(l+n)/2,E); draw(k--l--n--k); mra(k,n,l,0.3); [/asy]