A rectangle is a quadrilateral because it has four sides. In a rectangle, there are four right angles which means each angle has a measure of \(90^\circ\). The opposite sides of the rectangle are parallel to each other. It implies that a rectangle is also a parallelogram because it has two pairs of parallel sides.

## Perimeter of Rectangle

A rectangle has a perimeter equal to the sum of all its sides. The shorter side of the rectangle is called the width while the longer side is called the length. Since the opposite sides are congruent, then we will have two widths and two lengths. If the width is \(w\) and the length is \(l\), the perimeter of the rectangle is \(P=w+w+l+l\) which can be simplified as \(P=2w+2l\).