\PGset[0.8em]

\begin{picture}   (12, 6 )
\drawline     (  1, 1 )( 11, 1) ( 8.333, 5 )( 1, 1 ) % A(O)BCA
\dashline[80]{0.2}( 8.333, 4.8 )( 8.333, 1) % CO

\put( 0.7  , 0.2 ){$\scriptstyle A$}
\put( 8.0  , 0.2 ){$\scriptstyle O$}
\put( 8.0  , 5.2 ){$\scriptstyle C$}
\put(10.3  , 0.2 ){$\scriptstyle B$}
\end{picture}

\quad

\begin{picture}   (17, 8 )
\drawline     (  1, 1 )( 16, 1 )( 12, 7 )( 1, 1 )     % A'(O')B'C'A'
\dashline[80]{0.2}( 12, 6.8 )( 12, 1 ) % C'O'

\put( 0.7  , 0.2 ){$\scriptstyle A'$}
\put(11.7  , 0.2 ){$\scriptstyle O'$}
\put(11.7  , 7.2 ){$\scriptstyle C'$}
\put(15.3  , 0.2 ){$\scriptstyle B'$}
\end{picture}

\PGrestore