Geometry

Regular Polygon Apothem

Apothem (incircle radius) of a regular n-gon.

Formula

Formula
a = s2 tan(πn)

Variables

SymbolDefinitionType & rangeUnitsRole
n number of sides integer (ℤ) input
s side length real number (ℝ) input

Try it yourself

Interactive calculator
Result

Worked examples

Example 1
Givensides n = 6, side s = 4
Result3.464101615
Example 2
Givensides n = 4, side s = 10
Result5