How To Calculate The Perimeter Of A Shape

The perimeter of shapes is the summation of the length of each side of a shape. Perimeter for a circle is different: when a diameter equals one, then the perimeter equals pi. Contractors use perimeter for things such as to determine lengths of fences or putting a border around a room.

Non-Circular Shapes

Step 1

Measure the length of each side of a shape. For example, a parallelogram may have sides of 3 inches, 3 inches, 5 inches and 5 inches.

Step 2

Add the sides together. In the example, 3 plus 3 plus 5 plus 5 equals a perimeter of 16 inches.

Step 3

Recalculate the perimeter to check your work. Since perimeter calculations involve adding three or more sides, each additional side adds to the chance of making a calculation error.

Circle

Step 1

Measure the diameter of the circle. The diameter is the length from one end of a circle to the opposite end of the circle. For example, a circle may have a diameter of 10 inches.

Step 2

Divide the diameter into two to determine the radius. In the example, the radius of the circle is 5 inches.

Step 3

Multiply 2 by the radium and pi. In the example, 2 times 5 times 3.14, which equals a perimeter of 31.4 inches.

Step 4

Recalculate the perimeter to check your work and eliminate the chances of a mathematical error.

Cite This Article

MLA

McBride, Carter. "How To Calculate The Perimeter Of A Shape" sciencing.com, https://www.sciencing.com/calculate-perimeter-shape-6362461/. 24 April 2017.

APA

McBride, Carter. (2017, April 24). How To Calculate The Perimeter Of A Shape. sciencing.com. Retrieved from https://www.sciencing.com/calculate-perimeter-shape-6362461/

Chicago

McBride, Carter. How To Calculate The Perimeter Of A Shape last modified March 24, 2022. https://www.sciencing.com/calculate-perimeter-shape-6362461/

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