Polygon Angle Calculator

Calculate interior and exterior angles of regular polygons with detailed explanations

Calculate Polygon Angles

Minimum 3 sides required for a polygon

Choose your preferred angle measurement unit

Example Calculations

Regular Hexagon (6 sides)

Interior angle: (6-2)π/6 = 4π/6 = 2π/3 ≈ 2.094 rad

In degrees: 2π/3 × 180°/π = 120°

Exterior angle: 2π/6 = π/3 ≈ 1.047 rad = 60°

Sum of interior angles: (6-2) × 180° = 720°

Regular Octagon (8 sides)

Interior angle: (8-2)π/8 = 6π/8 = 3π/4 ≈ 2.356 rad

In degrees: 3π/4 × 180°/π = 135°

Exterior angle: 2π/8 = π/4 ≈ 0.785 rad = 45°

Sum of interior angles: (8-2) × 180° = 1080°

Common Polygon Angles

Triangle (3)60°
Square (4)90°
Pentagon (5)108°
Hexagon (6)120°
Octagon (8)135°
Decagon (10)144°

Interior angles in degrees

Polygon Facts

Sum of exterior angles is always 360° for any polygon

Interior + Exterior angle = 180° (supplementary)

As sides increase, interior angles approach 180°

Regular polygons have all equal sides and angles

Central angle equals exterior angle in regular polygons

Understanding Polygon Angles

Interior Angles

Interior angles are formed inside the polygon at each vertex where two sides meet. In a regular polygon, all interior angles are equal.

Key Properties

  • Formula: α = (n-2) × 180° / n
  • Sum of all interior angles: (n-2) × 180°
  • Always less than 180° in convex polygons
  • Approaches 180° as sides increase

Exterior Angles

Exterior angles are formed between one side of the polygon and the extension of an adjacent side. They're also equal to the central angles in regular polygons.

Key Properties

  • Formula: β = 360° / n
  • Sum of all exterior angles: always 360°
  • Supplementary to interior angle (sum = 180°)
  • Equals central angle in regular polygons

Formulas in Radians

Interior angle: α = (n-2)π/n

Exterior angle: β = 2π/n

Sum of interior angles: (n-2)π

Sum of exterior angles:

Applications

  • Architecture and construction
  • Computer graphics and game design
  • Engineering and mechanical design
  • Art and geometric patterns