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How to use Regular Polygon Calculator

Enter the number of sides and the side length and the calculator returns angles, perimeter, apothem, area and circumradius.

Frequently asked questions

How is the interior angle of a regular polygon found?

Interior angle = (n−2) × 180° / n, where n is the number of sides.

What is the apothem?

The distance from the center to the midpoint of a side; it equals s / (2 tan(π/n)) for side length s.

How is the area calculated?

Area = (1/2) × perimeter × apothem, or equivalently (1/4)n·s²·cot(π/n).

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