A trapezoid is a four sided polygon, such that, one pair of opposite sides is parallel to each other. Figure 3.5 shows a trapezoid ABCD.
The parallel sides of a trapezoid are called bases and the non parallel sides are called legs. The line joining the mid points of the legs in a trapezoid is parallel to the bases and is called the median.
In figure 3.6 ABCD is a trapezoid. P is the midpoint of AD and Q is the midpoint of BC. Segment PQ is parallel to both AB and DC and is called the median of ABCD. The median is always half of the sum of the bases,
The distance between the bases ( parallel sides ) of a trapezoid is measured by the perpendicular line joining the two bases. It is called the attitude of the trapezoid. In Figure 3.7 AX and BY are the attitudes of trapezoid ABCD.