How to change the "curliness" of Matrix brackets?

Question

How can I get my matrix brackets to look like the above instead of:

My current one uses the following packages and has the latex:

\documentclass[12pt]{article}
    \usepackage[a4paper]{geometry}
    \usepackage{amsmath}
    \usepackage{amssymb}
\begin{document}
$\vec{r}\cdot\begin{pmatrix} 3 \\2\\4 \end{pmatrix}=12$
\end{document} 

Answer 1

\documentclass[12pt]{article}
\usepackage[a4paper]{geometry}
\usepackage{amsmath}
\usepackage{amssymb}
\begin{document}
$\vec{r}\cdot\left\lgroup\begin{matrix} 3 \\2\\4 \end{matrix}\right\rgroup=12$
\end{document}