How do you calculate the perimeter of a rectangle by adding side lengths?

To calculate the perimeter of a rectangle, add the lengths of all four of its sides. For the rectangle shown, the side lengths are 2 ft, 6 ft, 2 ft, and 6 ft, giving the expression

P = 2 + 6 + 2 + 6

Conditions

Use all side lengths of the shape.
Units must be consistent; here all lengths are in feet.

Reasoning, step by step

Identify the lengths of all four sides of the rectangle.
Write an expression adding all four side lengths together.
Compute the sum to find the total perimeter.
Attach the unit of measure to the final numerical result.

Example

For a rectangle with sides 2 ft, 6 ft, 2 ft, and 6 ft, the perimeter is calculated as $P = 2 + 6 + 2 + 6 = 16$ ft.

Common misconceptions

Only adding two adjacent sides instead of all four sides.
Forgetting to include the unit of measurement in the final answer.

Watch the explanation

YouTubePerimeter, Area, and Volume Explained | Math with Mr. J

0:34 – 1:30Watch this moment ↗

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