Triangle A three-sided polygon. Identifying Quadrilaterals Quadrilaterals are four-sided polygons. Study the figures below. They are four special quadrilaterals. Any four-sided figure with two pairs of parallel sides is a parallelogram .
Parallel sides are lines that never intersect or meet.
A rectangle is a parallelogram with four right angles. A square is a rectangle with four equal sides. The community at the right contains many different parallelograms. The area of the police building is found by counting the squares. The police building has 32 square units of area.