Math

Polygon angle sums.

Definition

The sum of interior angles of a polygon depends on the number of sides. For any n-sided polygon, the interior angle sum is (n-2) × 180°. Each exterior angle and its adjacent interior angle sum to 180°.

Examples

Real-world.

  • 1 Triangle: (3-2) × 180° = 180°
  • 2 Pentagon: (5-2) × 180° = 540°
  • 3 Each interior angle of a regular hexagon: 720°/6 = 120°
Key Fact

Interior angle sum = (n-2) × 180°; Exterior angle sum always = 360°

Studied in

1 unit use this concept.