6.1 Polygons

Convex verse Concave

Definition of a Polygon

A polygon is a figure on a plane with three or more sides that meet at a vertex.

AB

C

D

Vertex

Side

Name of this Polygon

ABCD, CDAB, or DABC

You want to list the vertices in some order.

AB

C

D

Vertex

Side

Polygons are named by their sides

3 sides – Triangle4 sides – Quadrilateral5 sides – Pentagon 6 sides – Hexagon7 sides – Heptagon8 sides – Octagon9 sides – Nonagon10 sides – Decagon11 sides - Hendecagon 12 sides – Dodecagon13 sides - Tridecagon or Triskaidecagon14 sides - Tetradecagon or Tetrakaidecagon 14 N sides – n-gon

Polygons are named by their sides

3 sides – Triangle4 sides – Quadrilateral5 sides – Pentagon 6 sides – Hexagon7 sides – Heptagon8 sides – Octagon9 sides – Nonagon10 sides – Decagon11 sides - Hendecagon 12 sides – Dodecagon13 sides - Tridecagon or Triskaidecagon14 sides - Tetradecagon or Tetrakaidecagon 14 N sides – n-gon

Polygons are named by their sides

3 sides – Triangle4 sides – Quadrilateral5 sides – Pentagon 6 sides – Hexagon7 sides – Heptagon8 sides – Octagon9 sides – Nonagon10 sides – Decagon11 sides - Hendecagon 12 sides – Dodecagon13 sides - Tridecagon or Triskaidecagon14 sides - Tetradecagon or Tetrakaidecagon 14 N sides – n-gon

Polygons are named by their sides

3 sides – Triangle4 sides – Quadrilateral5 sides – Pentagon 6 sides – Hexagon7 sides – Heptagon8 sides – Octagon9 sides – Nonagon10 sides – Decagon11 sides - Hendecagon 12 sides – Dodecagon13 sides - Tridecagon or Triskaidecagon14 sides - Tetradecagon or Tetrakaidecagon 14 N sides – n-gon

Polygons are named by their sides

3 sides – Triangle4 sides – Quadrilateral5 sides – Pentagon 6 sides – Hexagon7 sides – Heptagon8 sides – Octagon9 sides – Nonagon10 sides – Decagon11 sides - Hendecagon 12 sides – Dodecagon13 sides - Tridecagon or Triskaidecagon14 sides - Tetradecagon or Tetrakaidecagon 14 N sides – n-gon

Polygons are named by their sides

3 sides – Triangle4 sides – Quadrilateral5 sides – Pentagon 6 sides – Hexagon7 sides – Heptagon8 sides – Octagon9 sides – Nonagon10 sides – Decagon11 sides - Hendecagon 12 sides – Dodecagon13 sides - Tridecagon or Triskaidecagon14 sides - Tetradecagon or TetrakaidecagonN sides – n-gon

Polygons are named by their sides

3 sides – Triangle4 sides – Quadrilateral5 sides – Pentagon 6 sides – Hexagon7 sides – Heptagon8 sides – Octagon9 sides – Nonagon10 sides – Decagon11 sides - Hendecagon 12 sides – Dodecagon13 sides - Tridecagon or Triskaidecagon14 sides - Tetradecagon or Tetrakaidecagon 14 N sides – n-gon

Polygons are named by their sides

3 sides – Triangle4 sides – Quadrilateral5 sides – Pentagon 6 sides – Hexagon7 sides – Heptagon8 sides – Octagon9 sides – Nonagon10 sides – Decagon11 sides - Hendecagon 12 sides – Dodecagon13 sides - Tridecagon or TriskaidecagonN sides – n-gon

Definition of Convex and Concave polygons

A polygon is convex if any line can pass through two points in the polygon and without going outside of the polygon.

Concave

Remember definitions

Equilaterial – All sides equal

Equilangluar – All angles equal

Regular Polygon

– All sides and angles equal.

Regular Polygon – All sides and angles equal

Theorem

The interior angles of a Quadrilateral add to 360º

The interior angles of any polygon is

(n – 2) x 180º

Where n is the number of sides

FHEG ;

H G

FE55

x

x

x

______

______

_____

55

Gm

Fm

Hm

Em

Homework Homework

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