quadrilateral

In geometry, a quadrilateral is a four-sided polygon, having four edges and four vertices.

\documentclass[margin={6cm 0cm}]{standalone}
\usepackage{tikz}
%
\begin{document}
\begin{tikzpicture}
    \draw [very thick] (1,0) -- (2,2) -- (5,2) -- (0,5) -- cycle;
\end{tikzpicture}
\hspace{1cm}
\begin{tikzpicture}
    \draw [very thick] (0,0) -- (4,2) -- (4,5) -- (0,5) -- cycle; 
\end{tikzpicture}
\hspace{1cm}
\begin{tikzpicture}
    \draw [very thick] (2,0) -- (5,4) -- (4,5) -- (0,2) -- cycle;
\end{tikzpicture}
\end{document}

A quadrilateral with vertices $A,B,C,D$ would be denoted $◻ABCD$.

Quadrilaterals are simple or complex.
Simple quadrilaterals are either concave or convex.

The interior angles of a simple planar quadrilateral sum to $360\text{°}$.
Formally, for a quadrilateral $◻ABCD$,

From Latin quadri 'four' and latus 'side'
Also called tetragon, from Greek tetra 'four' and gon 'corner' or 'angle'

Quadrilaterals can be classified by their characteristics:

• kite : reflection symmetry across a diagonal
• trapezoid : one set of parallel sides and other two sides congruent
• parallelogram : two sets of parallel sides
• rhombus : four equal sides
• rectangle : four equal angles
• square : four equal sides, four equal angles

!Quadrilateral Heirarchy.canvas