%% 
%%  Example 02-02-2 
%%  Copyright (C) 2016 Herbert Voss
%% 
%% ==== 
% Show page(s) 1
%% 
%% 
\documentclass[]{screxa}
\pagestyle{empty}
\setlength\textwidth{158.31393pt}
\setlength\parindent{0pt}
%StartShownPreambleCommands
\usepackage{amsmath}
%StopShownPreambleCommands
\begin{document}
\begin{align}
\rule{2cm}{1pt}
\begin{gathered}
\quad i_{11}=0.25\\
\quad i_{21}=\frac{1}{3}i_{11}\\
\quad i_{31}=0.33i_{22}
\end{gathered}
\rule{2cm}{1pt}
\end{align}
\end{document}
