This lesson goes over how to find the perimeter of a rectangle and a square. Here are some definitions to help you with this lesson:

**Perimeter:**The length of the outside edge.**Rectangle**: A four sided shape whose opposite sides are the same length and all the corners form right angles.

**Square**: A four sided rectangle where all sides are the same length.

### Real World Application

A right angle is also a 90 degree angle. We won’t go into angles in this course but it is good to have a basic understanding of this vocabulary.

Perimeter of a Rectangle

Video Source (04:22 mins) | Transcript

Perimeter is the sum of the outside edge lengths. For rectangles and squares we can simplify this because some of the side lengths are the same. (L = length, W = width)

Perimeter of a rectangle: \(L + L + W + W = 2L + 2W\) (By combining like terms.)

Perimeter of a square: \(W + W + W + W = 4W\)

## Additional Resources

- Khan Academy: Introduction to Perimeter (3:20 mins; Transcript)

### Practice Problems

- The top of a pizza box forms a square where each side is 35 cm. Find the perimeter of the square defined by this pizza box. (Video Solution
- A rectangular swimming pool has a length of 20 ft and a width of 12 ft. Find the perimeter of the rectangle defined by this swimming pool. (Solution
- The borders for the state of Colorado form a rectangle that measures about 360 miles long and 280 miles wide. Find the perimeter of the rectangle defined by this state. (Video Solution
- A rectangular flag has a length of 150 cm and a width of 120 cm. Find the perimeter of the rectangle defined by this flag. (Solution
- The cover of a book has a length of 5 in and a width of 8 in. Find the perimeter of the rectangle defined by this book cover. (Solution
- A basketball court is rectangular in shape with a length of 29 m and a width of 15 m. Find the perimeter of the rectangle defined by this court. (Solution

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