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Side Length of N Gon Calculator

Reviewed by Calculator Editorial Team

A regular n-sided polygon (n-gon) is a polygon with n equal sides and n equal angles. This calculator determines the side length of a regular n-gon when given either the perimeter or the circumradius.

What is an N-gon?

A regular n-gon is a polygon with n sides where all sides are equal in length and all interior angles are equal. Common examples include equilateral triangles (3-gons), squares (4-gons), regular pentagons (5-gons), and regular hexagons (6-gons).

Regular n-gons are used in architecture, engineering, and design due to their symmetry and predictable properties. The side length is a fundamental property that determines the polygon's size and shape.

Formula for Side Length

The side length (s) of a regular n-gon can be calculated using two main formulas:

When perimeter is known:

s = Perimeter / n

Where:

  • s = side length
  • Perimeter = total distance around the polygon
  • n = number of sides

When circumradius is known:

s = 2 × R × sin(π/n)

Where:

  • s = side length
  • R = circumradius (distance from center to a vertex)
  • n = number of sides

The calculator uses these formulas to provide accurate results based on your input.

How to Use the Calculator

  1. Enter the number of sides (n) of your polygon.
  2. Choose whether you know the perimeter or the circumradius.
  3. Enter the known value in the appropriate field.
  4. Click "Calculate" to determine the side length.
  5. Review the result and use the chart to visualize the relationship between sides and perimeter.

Worked Examples

Example 1: Square (4-gon)

Given a square with perimeter 20 units:

Side length = 20 / 4 = 5 units

Example 2: Regular Hexagon (6-gon)

Given a regular hexagon with circumradius 10 units:

Side length = 2 × 10 × sin(π/6) ≈ 2 × 10 × 0.5 = 10 units

Polygon Perimeter Side Length
Equilateral Triangle (3-gon) 18 units 6 units
Square (4-gon) 20 units 5 units
Regular Pentagon (5-gon) 25 units 5 units

FAQ

What is the difference between a regular and irregular n-gon?

A regular n-gon has all sides and angles equal, while an irregular n-gon has sides and angles of different measures.

Can I use this calculator for non-integer values of n?

Yes, the calculator accepts any positive real number for n, though polygons with non-integer sides are typically theoretical.

What is the smallest possible n-gon?

The smallest n-gon is a digon (n=2), though it's not commonly used in practical applications.