GKT101: General Knowledge for Teachers – Math

A trapezoid is a quadrilateral with exactly one pair of parallel sides.

 

The Properties of a Trapezoid:

1. One pair of opposite sides are parallel, i.e., $\begin{align*}AB \parallel CD\end{align*}$.

2. The two pairs of adjacent angles along the sides are supplementary, i.e., $\begin{align*}\angle{ABC} + \angle{BCD} = 180^\circ\end{align*}$and $\begin{align*}\angle{CDA} + \angle{DAB} = 180^\circ\end{align*}$.

Note: Some texts leave out the word "exactly", which means quadrilaterals with two pairs of parallel sides are sometimes considered trapezoids. In this course, assume trapezoids have exactly one pair of parallel sides.