4. Sort each shape by whether it has any parallel or perpendicular sides.

When sorting shapes, look for pairs of sides that either never meet (parallel) or intersect at right angles (perpendicular). For example, a rectangle has both parallel and perpendicular sides; the opposite sides are parallel, and each corner forms perpendicular intersections. On the other hand, a trapezoid has one pair of parallel sides but may not necessarily have perpendicular sides, depending on its angles. To avoid common mistakes, remember to double-check that your definition of parallel means the sides will never intersect and that perpendicular sides are forming a 90-degree angle. Also, shapes like rhombuses and squares may appear tricky since all their sides are equal, but they still exhibit both parallel and perpendicular properties!