Regular N-gon Calculator

Universal calculator for all regular polygons

N-gon Calculator

Universal Polygon Calculator

A regular N-gon has N equal sides and N equal angles. Universal formulas for all polygons.

Enter parameter and number of vertices
Which parameter is known?
Value of the selected parameter
Polygon: N = 3, 4, 5, 6, 7, 8, 9, 10, ...
Quick selection of known polygons
Click on a number to automatically set N
Calculation Results
Edge length a:
Perimeter P:
Area A:
Circumcircle radius ra:
Incircle radius ri:
Interior angle α:

Regular N-gon

The diagram shows an example polygon with inscribed and circumscribed circles.
All N sides are equal in length, all interior angles are equal.

N-gon Example

The universal N-gon calculator

A regular N-gon is the most general form of a regular polygon:

  • N equal sides: All side lengths are identical
  • N equal angles: Each interior angle = 180°(N-2)/N
  • Sum of angles: (N-2) × 180°
  • Central angle: 360°/N per segment
  • N-fold symmetry: Rotational and reflection symmetry
  • Universal formulas: Work for all N ≥ 3

Universal polygon formulas

These universal formulas work for all regular polygons:

Basic formulas
  • Perimeter: P = N · a
  • Area: A = (N/4) · cot(π/N) · a²
  • Interior angle: α = 180°(N-2)/N
  • Central angle: β = 360°/N
Circle relationships
  • Circumradius: rₐ = a/(2·sin(π/N))
  • Inradius: rᵢ = a/(2·tan(π/N))
  • Ratio: rₐ/rᵢ = 1/cos(π/N)
  • Apothem = Inradius

Known polygon examples

Overview of the most common regular polygons and their properties:

Basic polygons
  • N=3: Triangle (60° interior angle)
  • N=4: Square (90° interior angle)
  • N=5: Pentagon (108° interior angle)
  • N=6: Hexagon (120° interior angle)
Extended polygons
  • N=8: Octagon (135° interior angle)
  • N=10: Decagon (144° interior angle)
  • N=12: Dodecagon (150° interior angle)
  • N→∞: Circle (180° limit angle)

Applications of the N-gon calculator

The universal N-gon calculator finds versatile applications:

Technical design
  • CAD programs and technical drawings
  • Mechanical engineering components
  • Architectural floor plans
  • Precision tools
Education & research
  • Mathematics education and geometry
  • Engineering sciences
  • Crystallography and materials science
  • Computer graphics and animation
Industry & production
  • Manufacturing and punching technology
  • Optical systems and prisms
  • Packaging industry
  • Jewelry and watch manufacturing
Creativity & games
  • Game development and level design
  • Puzzles and brain games
  • Art projects and installations
  • 3D printing and prototyping

Universal formulas for regular N-gons

Area A
\[A = \frac{N}{4} \cdot \cot\left(\frac{\pi}{N}\right) \cdot a^2\]

Universal area formula for all N

Perimeter P
\[P = N \cdot a\]

Simple: N times the side length

Circumradius rₐ
\[r_a = \frac{a}{2\sin(\pi/N)}\]

Radius of the circumcircle

Inradius rᵢ
\[r_i = \frac{a}{2\tan(\pi/N)}\]

Apothem (radius of the incircle)

Interior angle α
\[\alpha = \frac{180°(N-2)}{N}\]

Each interior angle of the N-gon

Central angle β
\[\beta = \frac{360°}{N}\]

Angle between two radii

Radius ratio
\[\frac{r_a}{r_i} = \frac{1}{\cos(\pi/N)}\]

Circumradius to inradius ratio

Circle approximation
\[\lim_{N \to \infty} A = \pi r_a^2\]

For large N, the polygon approaches a circle

Calculation example for an N-gon

Given
Side length a = 5 Number of vertices N = 6 (Hexagon)

Find: All properties of the regular hexagon

1. Calculate basic measures
\[P = 6 \times 5 = 30\] \[A = \frac{6}{4} \cdot \cot(30°) \cdot 25 = 64.95\]

Perimeter and area

2. Radii and angles
\[r_a = \frac{5}{2\sin(30°)} = 5.00\] \[r_i = \frac{5}{2\tan(30°)} = 4.33\] \[\alpha = \frac{180° \cdot 4}{6} = 120°\]

Circumradius, inradius and interior angle

3. Universal formulas in action
Central angle = 60° Sum of angles = 720° Ratio rₐ/rᵢ = 1.155
sin(30°) = 0.5 tan(30°) = 0.577 cot(30°) = 1.732

All values result from the universal N-gon formulas

4. Complete N-gon analysis
N = 6 vertices a = 5.00 side length P = 30.00 perimeter A = 64.95 area
rₐ = 5.00 circumradius rᵢ = 4.33 inradius α = 120° interior angle β = 60° central angle

The universal N-gon calculator works for all regular polygons!

The universal N-gon calculator: Geometry unified

The universal N-gon calculator is the most powerful tool in polygon geometry. With a single set of formulas, all regular polygons from N=3 to N→∞ can be calculated. It unites the entire diversity of regular polygons in elegant mathematical expressions.

The power of universal formulas

The mathematical beauty lies in the universality of trigonometry:

  • One parameter N determines everything: All properties derive from the number of vertices
  • Trigonometric elegance: sin(π/N), cos(π/N), tan(π/N) as basis
  • Continuous transition: From N=3 (triangle) to N→∞ (circle)
  • Scale invariance: Formulas work for any size
  • Construction theory: Connection to Gaussian constructibility

From finite to infinite: The transition to the circle

The N-gon calculator shows the fascinating transition from polygons to circles:

Convergence behavior

With increasing N, all polygon properties approach those of the circle. Already at N=20, the difference is visually barely noticeable.

Archimedes' method

Archimedes already used this idea in 250 BC for π approximation: He calculated N-gons with N=96 for precise π values.

Modern applications

In computer graphics, circles are approximated by N-gons with high N. The universal formulas enable efficient calculations.

Limit values

lim(N→∞) sin(π/N)/(π/N) = 1 and similar limits show the deep connection between geometry and analysis.

Practical applications in science and technology

The universal N-gon calculator finds wide practical application:

  • CAD software: Automatic polygon generation for technical drawings
  • Crystallography: Analysis of N-fold symmetric crystal structures
  • Optics: Calculation of prisms and optical elements
  • Mechanical engineering: Gears, couplings and rotationally symmetric parts
  • Architecture: Floor plans with special symmetries
  • Packaging technology: Optimal space utilization with polygonal cross-sections

Education and research

As a universal tool, the N-gon calculator serves various educational goals:

Mathematical education

Students can experimentally discover how polygon properties change with N. Trigonometry becomes tangible and clear.

Engineering education

Future engineers learn to work with parametric geometry systems and their practical application.

Research

In materials science, N-gon calculations help understand quasicrystals and complex symmetries.

Computational Geometry

Algorithms for polygon processing are based on universal N-gon formulas for efficiency and accuracy.

Summary

The universal N-gon calculator is more than just a calculation tool - it is a window into the fundamental unity of geometry. It shows how all regular polygons follow a common mathematical logic and how discrete shapes continuously evolve into circles. From practical application in engineering and design to theoretical exploration of geometric principles, it unites simplicity with power. It demonstrates that behind the apparent diversity of the polygon world stand elegant, universal laws that describe both the equilateral triangle and the approximately circular 1000-gon. In a world increasingly shaped by parametric geometry and algorithmic design, the universal N-gon calculator remains a fundamental and indispensable tool.

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