Polygons

1
Polygons Polyhedra

• Chapter 4 Lesson 2

2
Vocabulary - Polygons

• Polygon
• Is a two-dimensional closed plan figure formed by
  joining three or more line segments at they
  endpoints.
• Side
• Each line segment
• Vertex
• The point at which two sides meet

3
Vocabulary - Polygons

• A polygon is regular if all its sides are
  congruent (of equal length) and all its angles
  are congruent.
• A regular polygon is equilateral and equiangular

4
Vocabulary - Triangles

• Equilateral triangle
• Has three sides of equal lengths
• Isosceles triangle
• Has two sides of equal length
• Scalene triangle
• Has no sides of equal lengths
• Equiangular triangle
• Has three angles of equal measure

5
Vocabulary - Polyhedron

• Polyhedron
• A three-dimensional closed figure formed by
  joining three or more polygons at their sides.
• Each polygon of the polyhedron is called a face
  and joints multiple polygons along their sides.
• Edge
• The line segment at which two faces meet
• Vertex
• The point where three or more edges meet

6
Polygon Names

• 3 Sides
• Triangle

• 4 Sides
• Quadrilateral

• 5 Sides
• Pentagon

• 6 Sides
• Hexagon

7
Polygon Names

• 7 Sides
• Heptagon

• 8 Sides
• Octagon

• 9 Sides
• Nonagon

• 10 Sides
• Decagon

8
Polygon Names

• 11 Sides
• Hendecagon

• 12 Sides
• Dodecagon

• n Sides
• n-gon

9
Triangles

• Equilateral Triangle
• All sides are equal

• Isosceles Triangle
• Two sides equal

• Scalene Triangle
• No sides equal

• Equiangular Triangle
• All angles are equal