With this code:
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[scale=2]
\draw[] (-1,0) -- (3,1) node[pos=.5,sloped] () {\bfseries $\arrowvert$};
\draw[] (3,1) -- (5,-1) node[pos=.5,sloped] () {\bfseries $\Arrowvert$};
\draw[] (5,-1) -- (-1,0) node[pos=.5,sloped] () {\bfseries $\times$};
\end{tikzpicture}
\end{document}
You have this output:
ADD: With this code:
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw[line width=2pt] (-1,-2)--(2,3) node[pos=.5,sloped] () {\bfseries $\arrowvert$};
\draw[line width=2pt] (2,3)--(5,2) node[pos=.5,sloped] () {\bfseries $\Arrowvert$};
\draw[line width=2pt] (5,2)--(2,-3) node[pos=.5,sloped] () {\bfseries $\arrowvert$};
\draw[line width=2pt] (2,-3)--(-1,-2) node[pos=.5,sloped] () {\bfseries $\Arrowvert$};
\end{tikzpicture}
\end{document}
You can mark equals sides with the same symbol:
sloped
node with text/
or similar on the line, i.e.\draw (0,1)--node[sloped]{/} (1,1);
. For more complex marking, thepic
function was made for this. Finally, there's thedecoration.markings
library that provides the same functionality (and a bit more) but I don't think you need that if you would allow a slightly different syntax.