An octagon is an eight-sided figure, two-dimensional figure. You might need to find the area of an octagon is you were making a stop sign or if you were building an octagonal ring for an Ultimate Fighting Championship-style event. To calculate the area of an octagon, you need to know the length of the sides or the length of the radius of the octagon.

- Skill level:
- Moderately Easy

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### Things you need

- Ruler
- Calculator

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## Instructions

- 1
Measure the length of side of the octagon with the ruler.

- 2
Square the length of the side. For example, if your sides are each 10 inches long, you would get 100.

- 3
Multiply the result from Step 2 by 4.84 to calculate the area of the octagon. For example, you would multiply 100 by 4.84 to find that the area equals 484 square inches.

## Using the Side Length

- 1
Measure the radius with your ruler. The radius is the distance from the centre of the octagon to the point where any two sides intersect.

- 2
Square the radius from Step 1. For example, if the radius equals 8 inches, you would get 64.

- 3
Multiply the result from Step 2 by 2.828 to calculate the area. For example, you would multiply 64 by 2.828 to find that the area of the octagon equals about 180.992 square inches.