Sides of a Rectangle

Sides of a Rectangle

How to solve the sides of a rectangle problems: property, example, and its solution.

Definition

A rectangle is a parallelogram whose interior angles are all right angles.

A rectangle is a parallelogram
whose interior angles are all right angles.

So a rectangle has all the properties of a parallelogram.

Property

The opposite sides of a rectangle are congruent.

Just like the sides of a parallelogram,
the opposite sides of a rectangle are congruent.

Example

If ABCD is a rectangle, find AC. AB = 12, AD = 5.

The blue sides are the opposite sides of the rectangle.
So AB = DC = 12.

See △ADC.
Its legs are 5 and 12.

So it's a (5, 12, 13) triangle.

So AC = 13.