%% 
%%  Ein Beispiel der DANTE-Edition
%%  
%%  7. Auflage
%% 
%%  Beispiel 28-01-17 auf Seite 597.
%% 
%%  Copyright (C) 2016 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
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%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{121.16928pt}
\setlength\parindent{0pt}
%StartShownPreambleCommands
\usepackage{pst-eucl}
%StopShownPreambleCommands
\begin{document}
\begin{pspicture}(-1.5,-1.5)(1.5,1.5)
  \psset{SegmentSymbol=pstslash}
  \pstTriangle[PosAngleB=90,
    linecolor=blue,linewidth=.5\pslinewidth]
    (-1.25,-1.25){A}(-1.25,1.25){B}(1.25,1.25){C}
  \pstRightAngle[linecolor=red]{C}{B}{A}
  \pstMarkAngle[Mark=MarkHash]{B}{C}{A}{$\theta$}
  \pstMarkAngle[Mark=MarkHash]{C}{A}{B}{$\beta$}
\end{pspicture}
\end{document}