A parallelogram has opposite sides equal in length and parallel. A trapezoid has at least 1 pair of parallel sides. EXAMPLE Classify a Quadrilateral 1 Classify the quadrilateral in as many ways as possible.It can be classified as a parallelogram, rectangle, square, and rhombus. 10-8 Quadrilaterals 0410-0413_CH10L8-105711.indd 410 7/20/09 11:41:30 AM.