How many pairs of equal sides has a rectangle?

A rectangle has two pairs of parallel and congruent sides. An equilateral rectangle, or square, has four equal sides.

Other quadrilaterals include trapezoids, which have two adjacent and equal sides, parallelograms, which have two pairs of parallel and congruent sides, and rhombi, which have four equal sides. (The a rectangle is a type of parallelogram. What differentiates it is angle configuration. A rhombus is likewise differentiated from a square by angle configuration.)