1. Brought to you by powerpointpros.com…

2. MENU Please select a particular lesson to learn. If no lesson is selected, the default mode is “Play All.” 1. What is a Polygon? What is a Polygon? 2. Naming Polygons Naming Polygons 3. Regular/ Irregular Polygons Regular/ Irregular Polygons 4. Concave/ Convex Polygons Concave/ Convex Polygons 5. Polygon Practice Polygon Practice PLAY ALL NOTE NOTE: Each section, when played by itself, will include a practice problem from the Polygon Practice section. If “Play All” is selected, practice problems will be saved for the end.

3. Section 1

4. Characteristics of Polygons A polygon must meet all 4 of these requirements: 1. A polygon must be a closed figure. 2. A polygon must be composed of 3 or more line segments. 3. A polygon must only have straight sides. 4. All lines of a polygon intersect only at vertices.

5. 1.A polygon must be a closed figure. What this statement means is that a polygon must not have any openings or breaks in the lines. Think of it like a fence. A polygon is like a fence that can’t have any gates or holes in it. POLYGON NOT A POLYGON

6. 2.A polygon must be composed of 3 or more line segments. This statement says that a shape must have 3 or more sides to be considered a polygon. POLYGON NOT A POLYGON REMEMBERING SKILLS This shape isn’t a polygon because it has only one “side.” Why else isn’t it a polygon?

7. 3.A polygon must only have straight sides. This requirement states that any shape that has a curved side isn’t a polygon, since a polygon’s sides must be straight. POLYGON NOT A POLYGON

8. 4.All lines of a polygon intersect only at vertices. Key Word: vertices (vertex, singular) The “corners” of a polygon, the point where sides end. This requirement states that a polygon’s sides can’t cross each other; sides that intersect must end at that intersecting point. POLYGON NOT A POLYGON

9. Review 1. A polygon must be a closed figure. 2. A polygon must be composed of 3 or more line segments. 3. A polygon must only have straight sides. 4. All lines of a polygon intersect only at vertices.

10. Section 2

11. How to Name a Polygon Polygons can be named by the number of sides that they have. In this presentation, we include the names of polygons with 3-10 sides, but there are names for polygons with more than 10 sides (but not less than 3, remember!)

12. Basic Names for Polygons Teacher Note This very same document is available for you to print out for your students at www.powerpointpros.com. It is listed as an additional resource under the Polygons PowerPoint post. www.powerpointpros.com

13. Other Names for Polygons There are other names for polygons as well, such as regular, irregular, concave, and convex. You can learn about those in the coming sections.

14. Section 3

15. Regular Polygons Key Word: regular polygon A polygon with congruent sides and angles. A regular polygon has congruent sides and angles. This means that all the sides should be exactly the same length, and all angles should measure the same number of degrees. REGULAR DECAGON

16. Irregular Polygons Key Word: irregular polygon A polygon that doesn’t have congruent sides and/or angles. An irregular polygon is, basically, the exact opposite of a regular polygon. IRREGULAR HEPTAGON

17. Section 4

18. Convex Polygons Key Word: convex polygon A polygon in which all diagonals from vertices are in the interior of the polygon. A convex polygon is a polygon where if you draw diagonal lines from any vertex to any other vertex, it will be in the interior of the polygon.

19. Let’s demonstrate, shall we? This is a convex hexagon. Here’s why: No matter how many times we “connect the vertices”, all the lines are in the interior of the hexagon.

20. Concave Polygons Key Word: concave polygon A polygon in which all diagonals from vertices are NOT in the interior of the polygon. A concave polygon is basically the exact opposite of a convex polygon.

21. Let’s demonstrate, shall we? This is a concave hexagon. Here’s why: This is a concave hexagon because when we connected two vertices together, the line went outside the hexagon.

22. Section 5

23. Practice  State why each shape isn’t a polygon.

24. Practice  State why each shape isn’t a polygon. It isn’t a closed figure. Why?

25. Practice  State why each shape isn’t a polygon. It isn’t a closed figure, and it isn’t made up of 3 or more sides. Why?

26. Practice  State why each shape isn’t a polygon. It is round. Why?

27. Practice  State why each shape isn’t a polygon. Its lines intersect at a place other than a vertex (corner). Why?

28. Practice  Name each polygon by the number of sides it has.

29. Practice  Name each polygon by the number of sides it has. This polygon is a… quadrilateral

30. Practice  Name each polygon by the number of sides it has. This polygon is a… heptagon

31. Practice  Name each polygon by the number of sides it has. This polygon is a… triangle

32. Practice  Name each polygon by the number of sides it has. This polygon is a… decagon

33. Practice  Name each polygon by the number of sides it has. This polygon is a… hexagon

34. Practice  Name each polygon as regular or irregular.

35. Practice  Name each polygon as regular or irregular. This polygon is a(n)… polygon. regular

36. Practice  Name each polygon as regular or irregular. This polygon is a(n)… polygon. regular

37. Practice  Name each polygon as regular or irregular. This polygon is a(n)… polygon. irregular

38. Practice  Name each polygon as regular or irregular. This polygon is a(n)… polygon. irregular

39. Practice  Name each polygon as regular or irregular. This polygon is a(n)… polygon. regular

40. Practice  Name each polygon as concave or convex.

41. Practice  Name each polygon as concave or convex. This polygon is a(n)… polygon. concave

42. Practice  Name each polygon as concave or convex. This polygon is a(n)… polygon. convex

43. Practice  Name each polygon as concave or convex. This polygon is a(n)… polygon. convex

44. Practice  Name each polygon as concave or convex. This polygon is a(n)… polygon. concave

45. Brought to you by powerpointpros.com