\begin{definition}[Definition:Quadrilateral/Parallelogram/Base]
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In a given parallelogram, one of the sides is distinguished as being the '''base'''.
It is immaterial which is so chosen, but usual practice is that it is one of the two longer sides.
In the parallelogram above, line $AB$ is considered to be the '''base'''.
Category:Definitions/Parallelograms
\end{definition}