1. How are polygons classified?
6-1B Exploring Polygons
How are polygons classified?

2. You measured one-dimensional figures.
Identify and name polygons.

3. Definitions
A polygon is a closed figure formed by a finite number of coplanar segments called sides such that
The sides that have a common endpoint are noncollinear, and
Each side intersects exactly two other sides, but only at their endpoints.

4. Definition
A vertex of a polygon is the vertex of each angle in the polygon.
A polygon is named by the letters of its vertices, written in order of consecutive vertices.

5. Definition
A convex polygon is one in which each diagonal (except its endpoints) is in the interior (inside) of the polygon.

6. Convex Polygons

7. Definition
A concave polygon is one in which at least one diagonal (except its endpoints) is not in the interior of the polygon.
Opps…

8. Concave Polygons

9. Not Polygons

10. Definition
An Equilateral polygon is a polygon in which all sides are congruent.

11. Definition
An Equiangular Polygon is a polygon in which all angles are congruent.

12. Definition
A regular polygon is a polygon that is both equilateral and equiangular.
An irregular polygon is a polygon that is not regular

13. Classification of Polygons
sides Triangle
sides Quadrilateral
sides Pentagon
sides Hexagon
sides Heptagon
sides Octagon
sides Nonagon
sides Decagon
sides Dodecagon
20 sides Icosagon
“n” sides n-gon
See page 57 for chart

14. Name and Classify Polygons
A. Name the polygon by its number of sides. Then classify it as convex or concave and regular or irregular.
There are 4 sides, so this is a quadrilateral.
No line containing any of the sides will pass through the interior of the quadrilateral, so it is convex.
The sides are not congruent, so it is irregular.
Answer: quadrilateral, convex, irregular

15. Name and Classify Polygons
B. Name the polygon by its number of sides. Then classify it as convex or concave and regular or irregular.
There are 9 sides, so this is a nonagon.
Lines containing some of the sides will pass through the interior of the nonagon, so it is concave.
Since the polygon is concave, it must be irregular.
Answer: nonagon, concave, irregular

16. Assignment 1-6
Page 61, 1-5, 11-16
You should have three answers for 1-2,
Name by the number of sides
Convex or concave
Regular or irregular