How to Get the Perimeter of a Regular Shape

A square's four equal sides and four equal angles make it a regular shape.

The measurements of a shape's sides and how those sides intersect define the shape's type. A regular shape refers to a regular polygon -- a closed two-dimensional shape with each side having the same length and each interior angle having the same measurement. Any object's perimeter measures the distance around it, with the perimeter given as a linear measurement. Though a regular shape's perimeter depends on all its sides, you can find the measurement by working with just the length of one of the shape's sides.

Things You'll Need

• Ruler

Instructions

1. Count the number of sides of the shape. For this example, let the shape be an octagon, which has eight sides.

2. Measure one side of the shape. For this example, let the side measure 3 inches.

3. Multiply the side's measurement by the shape's number of sides. Concluding this example, 3 inches multiplied by 8 equals 24 inches.

Tips & Warnings

• If the shape is irregular, then measure each side independently and sum all the measurements.

References

• Math Open Reference: Perimeter of a Polygon
• Math Goodies: Perimeter