$2 \vec{q}+3 \vec{r},|\vec{s}|=$ $\qquad$ .

Translate the above text into English, keeping the original text's line breaks and format, and output the translation result directly. 

However, since the provided text is already in a form that is commonly used in both English and mathematical notations, the translation would be the same:

$2 \vec{q}+3 \vec{r},|\vec{s}|=$ $\qquad$ .
11. $7 \sqrt{2}$.
$$
|\vec{s}|^{2}=|\vec{p}+2 \vec{q}+3 \vec{r}|^{2}=\vec{p}^{2}+4 \vec{q}^{2}+9 \vec{r}^{2}+4 \vec{p} \cdot \vec{q}+6 \vec{p} \cdot \vec{r}+12 \vec{q} \cdot \vec{r}=98 \text {, then }|\vec{s}|=7 \sqrt{2} \text {. }
$$