5. Let positive numbers $p, q, r$ satisfy $\frac{(p+q+r)^{2}}{p^{2}}=$ $\frac{2(p+q+r)^{2}}{q^{2}}=\frac{3(p+q+r)^{2}}{r^{2}}=k$, then the value of $k$ is $\qquad$.
5. $6+2(\sqrt{2}+\sqrt{3}+\sqrt{6})$