# Aligning an array with text beside it

I am trying to create a 'matrix' using the array environment. I have multiple of these lines each with text besides it of varying length. I would like to have the array aligned; however, in example below, the differing length of text changes that alignment

\documentclass{article}
\usepackage{gensymb}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{dcolumn}
\newcolumntype{R}{D{.}{.}{2,6}}
\begin{document}
$\left[ \begin{array}{@{}RR|R@{}} 0.28 &0.72 &45\\ 0.72 &0.28 &55\\ \end{array} \right] test$
$\left[ \begin{array}{@{}RR|R@{}} 0.28 &0.72 &45\\ 0.2016 &0.0784 &15.4\\ \end{array} \right] test1$
$\left[ \begin{array}{@{}RR|R@{}} 0.2016 &0.5184 &32.4\\ 0.2016 &0.0784 &15.4\\ \end{array} \right] test12$
\end{document}


I have tried using /hfill and the align/* environment with no success; however, my knowledge of latex is extremely limited.

I'd use aligned (and siunitx rather than dcolumn)

\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{siunitx}
\newcolumntype{R}[1]{S[table-format=#1]}

\begin{document}
\begin{aligned} \left[ \begin{array}{@{}R{2.4}R{2.4}|R{2.1}@{}} 0.28 &0.72 &45\\ 0.72 &0.28 &55\\ \end{array} \right] &\quad\text{test} \\ \left[ \begin{array}{@{}R{2.4}R{2.4}|R{2.1}@{}} 0.28 &0.72 &45\\ 0.2016 &0.0784 &15.4\\ \end{array} \right] &\quad\text{test1} \\ \left[ \begin{array}{@{}R{2.4}R{2.4}|R{2.1}@{}} 0.2016 &0.5184 &32.4\\ 0.2016 &0.0784 &15.4\\ \end{array} \right] &\quad\text{test12} \end{aligned}

\end{document}


You could place the right-hand text material into a fixed-width \parbox:

The fixed width chosen in the code below is 2cm; you're obviously free to adapt this width to your typesetting needs. Note also that the contents of a \parbox are typeset in text mode by default; this is true even if the \parbox occurs inside math mode.

\documentclass{article}
\usepackage{gensymb}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{dcolumn}
\newcolumntype{R}{D{.}{.}{2,6}}
\begin{document}
$\left[ \begin{array}{@{}RR|R@{}} 0.28 &0.72 &45\\ 0.72 &0.28 &55\\ \end{array} \right] \parbox{2cm}{test}$
$\left[ \begin{array}{@{}RR|R@{}} 0.28 &0.72 &45\\ 0.2016 &0.0784 &15.4\\ \end{array} \right] \parbox{2cm}{test1}$
$\left[ \begin{array}{@{}RR|R@{}} 0.2016 &0.5184 &32.4\\ 0.2016 &0.0784 &15.4\\ \end{array} \right] \parbox{2cm}{test12}$
\end{document}