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Apothem of a Regular Polygon Calculation

 
Select a polygon
Enter Side Length or Circumradius
Enter the Side Length: (a)
Enter the Circumradius: (R)
Enter the 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