# Regular polygon. Incircle and circumcircle

This online calculator determines parameters of circumcircle and incircle of a regular polygon

### This page exists due to the efforts of the following people:

#### Timur

Created: 2011-06-24 22:18:41, Last updated: 2020-11-03 14:19:28

This online calculator determines parameters of circumcircle and incircle of a regular polygon.

$r_i=\frac{a}{2tan(\pi/n)}$

Polygon area
$S_p=\frac{1}{2}nar_i$

$r_c=\frac{a}{2sin(\pi/n)}$

Polygon area
$S_p=\frac{na^2}{4tan(\pi/n)}$

#### Incircle of a regular polygon

Digits after the decimal point: 2

Incircle area

Polygon area

Area ratio

#### Circumcircle of a regular polygon

Digits after the decimal point: 2