Regular polygon area from circumcircle

Area of a regular polygon is the sum of area of a triangles it contains. Area of a triangle is
,
where a and b - triangle sides, and gamma is angle between those sides. For triangle in regular polygon a and b are circumradius, and gamma is 360/n, where n - number of sides. Thus area of polygon is
.
Calculator also displays area of the circumcircle, for reference

Regular polygon area from circumcircle

Circumradius

Number of sides

Calculation precision

Digits after the decimal point: 2

Calculate

Polygon area

 

Circumcircle area

 

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