Apothem of a Regular Polygon Calculator
In a polygon, a line to the midpoint of one of the sides from the center is called as apothem. Find the apothem of a regular polygon or circumradius of the incircle using this free online calculator.
Apothem of a Regular Polygon Calculation

Select a polygon:

Side Length or Circumradius:

Side Length (a):

Circumradius (R):

number of sides (n):

Apothem of a regular polygon (r):
Formula Used: 
r = a / [2 tan(π / n)] 
[or] 
r = R cos(π / n) 
r = Apothem of regular polygon 
R = Circumradius 
π = 3.14159... 
a = Side length 
n = Number of side 