Quadrilateral in which opposite sides are congruent and the four angles are right angles.

The

**length of a rectangle**is the longer of its two dimensions. The**width**is the shorter dimension..For measurement purposes, a distinction is sometimes made between the base *b* and the height *h* of a rectangle :

Either side of a rectangle may be used as a base; the adjacent side will then be the corresponding height.

### Properties

Based on its properties, a rectangle belongs to the larger category of convex quadrilaterals, which are trapezoids and parallelograms.

- Its two diagonals are congruent.
- Its opposite sides are parallel and congruent.
- A rectangle has two lines of symmetry.
- A rectangle is equiangular.

### Formulas

- The perimeter
*P*of a rectangle with a length of*l*and a width of*w*is :*P*= 2 × (*l*+*w*). - The area
*A*of a rectangle with a length of*l*and a width of*w*is :*A*=*l*×*w*.

### Example

The opposite sides of this rectangle are congruent.

Its four angles are right angles.

### Educational note

- A rectangle is a quadrilateral, since it is a parallelogram. Like a parallelogram, its sides are parallel in pairs. A parallelogram is also a trapezoid, as it has at least one pair of parallel sides.
- It may also be noted that a square is a rectangle, as all the angles in a square are right angles.