# What is a rectangle?

Unless you have sleep through every Geometry class this semester, it is safe to say you have heard the term rectangle. It is a very common geometric term, but what exactly is a rectangle? Let’s look at a list of the properties of a rectangle.
1. A rectangle is a quadrilateral so it has four sides.
2. It is a parallelogram so the opposite sides are parallel to each other.
3. The opposite sides of a rectangle are congruent. The top and bottom are different lengths than the sides.
4. A rectangle also has four right angles.
5. The perimeter of a rectangle can be found by adding the four sides together.( 2bases + 2heights)  or  P = 2(b+h)
6. The area of a rectangle is just base times height or  Area = bh
7. When you draw a diagonal inside a rectangle you create a right triangle. So the diagonal length is the hypotenuse of a right triangle. Therefore you can use the Pythagorean Theorem to find the length of the hypotenuse, which is your diagonal length.
For example, if your triangle had a height of 5 units and a base of 12 units the diagonal would be
For a visual explantation of rectangle properties please watch the video.