Area is the amount of space within a shape. To calculate a rectangle's area, multiply its length by its width. When calculating the area of a vertical rectangle, such as a window, use height instead of length.
For example, a rectangle is 3 feet long, and 4 feet wide. To calculate the area, do the following:
length = 3 feet
width  = 4 feet
area   = 3 feet × 4 feet = 12 square feet
To understand why the length is multiplied by the width, think of a rectangle as a grid of smaller squares. In the example above, think of the rectangle as having 3 rows, with each row having 4 squares. The rectangle would have a total of 12 squares.

Exercise 1 of 6

A bedroom is 11 feet long, and 12 feet wide. How many square feet is the area?

Exercise 2 of 6

A swimming pool is 16 feet long, and 32 feet wide. How many square feet is the area?

Exercise 3 of 6

A concert hall has rows A-Z, with each row having seats 1-36. How many seats are in the concert hall?

Exercise 4 of 6

A standard piece of paper is 8.5 inches long, and 11 inches wide. A door is 85 inches high, and 33 inches wide. How many pieces of paper would it take to cover the door? Divide the area of the door by the area of a piece of paper.

Exercise 5 of 6

A standard ping-pong table is 9 feet long, and 5 feet wide. A basketball court is 90 feet long, and 50 feet wide. How many ping-pong tables can fit on the basketball court?

Exercise 6 of 6

Central Park in New York City is 2.5 miles long, and 0.5 miles wide. Colorado is 280 miles long, and 380 miles wide. How many Central Parks can fit in Colorado?