Review of Quadrilaterals
Read this chapter, which summarizes all properties of various quadrilaterals, including the properties of their diagonals.
Quadrilaterals
The prefix "quad-" means "four", and "lateral" is derived from the Latin word for "side". So a quadrilateral is a four-sided polygon. Since it is a polygon, you know that it is a two-dimensional figure made up of straight sides. A quadrilateral also has four angles formed by its four sides.
![](https://learn.saylor.org/pluginfile.php/4150977/mod_book/chapter/34796/image.png)
,
,
and
are the sides and
,
,
and
are the vertices of the quadrilaterals.
Line segments and
joining two non-consecutive vertices are called diagonals.
Two sides like and
having a common endpoint are called adjacent sides.
There are many common special quadrilaterals that you should be familiar with. Below, these special quadrilaterals are described with their definitions and some properties.
Source: CK-12, https://flexbooks.ck12.org/cbook/ck-12-interactive-geometry-for-ccss/section/1.5/primary/lesson/quadrilaterals-geo-ccss/