How to Calculate the Perimeter of Quadrilaterals

When calculating the perimeter of any object, it's what's on the outside that counts. The perimeter of an object is the distance around it. A quadrilateral is a polygon, or 2-dimensional closed shape, with four sides. The most commonly recognized quadrilaterals include squares, rectangles and parallelograms, which are two pairs of parallel sides whose interior angles add up to 360 degrees -- as they do in all quadrilaterals. Calculating the perimeter of any quadrilateral depends on the lengths of its sides.

Instructions

1. Multiply the length of one side by four to calculate the perimeter of a square -- all of whose sides are equal in length. For example, if the side is 8 cm, then multiplying 8 by 4 results in 32 cm.

2. Add the width and length measurements together, and then multiply the sum by two to calculate the perimeter of a rectangle. For example, the width of the rectangle is 5 inches and its length is 2. Adding 5 and 2 together equals 7, and multiplying 7 by 2 equals 14. The perimeter of the rectangle is 14 inches.

3. Add the width and length measurements together, and then multiply the sum by two to calculate the perimeter of any parallelogram. For example, the parallelogram's width is 3 feet and its length is 7 feet. Adding 3 to 7 results in 10, and 10 multiplied by 2 equals 20 feet.

4. Add the lengths of all the sides together to calculate the perimeter of any quadrilateral. For example, a quadrilateral with sides measuring 2, 2, 4, and 7 meters has a perimeter of 2 + 2 + 4 + 7, which equals 15. The perimeter is 15 m.

References

• Math Open Reference: Quadrilateral Definition
• Algebra Lab: Areas and Perimeters of Triangles and Special Quadrilaterals
• Math.com: Perimeter
• Math is Fun: Polygons
• Birmingham Grid for Learning: Area and Perimeter

Resources

• Calculator's Edge: Perimeter Calculator