Polygons Basics

Polygons

Names of Polygons

• A polygon is a 2D shape with at least 3 sides
• Names of polygons based on the number of sides:
  • 3 sides: Triangle
  • 4 sides: Quadrilateral
  • 5 sides: Pentagon
  • 6 sides: Hexagon +...and so on

Number of Sides

• A polygon with:
  • 3 sides is a Triangle
  • 4 sides is a Quadrilateral
  • 5 sides is a Pentagon
  • 6 sides is a Hexagon
  • n sides is an n-gon

Interior Angles

• The sum of interior angles in a polygon with n sides is:
  • (n-2) × 180°
• Each interior angle of a regular polygon with n sides is:
  • (n-2) × 180° / n

Perimeter

• The perimeter of a polygon is the distance around the shape
• The perimeter of a polygon with n sides is the sum of the lengths of all its sides

Regular vs Irregular Polygons

• Regular Polygon: A polygon with all sides of equal length and all interior angles of equal measure
• Irregular Polygon: A polygon that is not regular, with sides and interior angles of different lengths and measures