1. POLYGONS

2. polygon not a polygon

3. A polygon is a plane figure. A polygon is a closed region. A polygon is formed by three or more segments as its sides. Each side of a polygon intersects only one segment at each of its endpoints. poli + gonus “many angled” What is a polygon?

4. Polygon or Not a Polygon? Polygon

5. Polygon or Not a Polygon? Not Polygon because sides are not segments.

6. Polygon or Not a Polygon? Not Polygon because sides are intersecting not just at the endpoints.

7. Polygon or Not a Polygon? Polygon

8. Polygon or Not a Polygon? Not Polygon because sides are intersecting not just at the endpoints.

9. Polygon or Not a Polygon? Polygon

10. Polygon or Not a Polygon? Not Polygon because sides are intersecting more than one other side at its endpoint.

11. Regions in a Polygon

12. Parts of a Polygon sides consecutive sides included angle nonconsecutive sides interior angles / vertex angles consecutive angles included side nonconsecutive angles exterior angles diagonals

13. ALL POLYGONS

14. ALL POLYGONS???

15. ALL POLYGONS!

16. How can these polygons be divided into two groups?

17. Convex Polygons Concave Polygons

18. Polygon Convexity A polygonal region is convex if any segment joining any two points of the polygon is part of the interior region. If a polygon is not convex, then its is concave.

19. Convex or Concave? Convex

20. Convex or Concave? Concave because a segment connecting points on the polygon that will lie in the exterior can be drawn.

21. Convex or Concave? Convex

22. Convex or Concave? Concave because a segment connecting points on the polygon that will lie in the exterior can be drawn.

23. Convex or Concave? Concave because a segment connecting points on the polygon that will lie in the exterior can be drawn.

24. Convex or Concave? Convex

25. Convex or Concave? Concave because a segment connecting points on the polygon that will lie in the exterior can be drawn.

26. Naming Polygons B A D C Polygons are named by writing their consecutive vertices in order, such as ABCD or CDAB for the polygon above. We cannot name the polygon as DBAC.

27. Connecting to Prior Knowledge Think of words beginning with the prefixes tri-, quad-, pent-, and oct-. Examples: triathlon, quadriplegic, pentameter, and octopus. Meanings? (words and prefixes)

28. Polygons can be named by their number of sides.

29. EQUIANGULAR POLYGON EQUILATERAL POLYGON REGULAR POLYGON Concept Emphasis

30. EQUILATERAL but not EQUIANGULAR EQUILATERAL and EQUIANGULAR ┌ ┌ ┌ ┌ EQUILATERAL and EQUIANGULAR EQUILATERAL but not EQUIANGULAR ┌ ┌ ┌ ┌