1. Polygons
Grade 6 Geometry

2. What is a Polygon???? .

3. A polygon is a closed plane figure with 3 or more sides, it must have all straight lines, no curves

4. Think, Pair, Share…
Look around the room, with a partner, make a list of polygons in the classroom.

5. Classifying Polygons by # of Sides
3 sided Polygon =
Triangle
Hint: Think “Tri”cycle, “tri”pod, “Tri”lateration (Tri means 3)

6. Classifying Polygons by # of Sides
4 sided Polygon =
Quadrilateral
Hint: Think “Quad”rant, “Quad”ruple, “Quad” (AKA 4-Wheeler)

7. Classifying Polygons by # of Sides
5 sided Polygon =
Pentagon
Hint: Think “Pent”athalon, or the government building “The Pentagon”

8. Classifying Polygons by # of Sides
6 sided Polygon =
Hexagon
Hint: Both “Hexagon” and “Six” have an ‘x’ in them

9. Classifying Polygons by # of Sides
7 sided Polygon =
Heptagon
Can you come up with a hint for remember a heptagon?

10. Classifying Polygons by # of Sides
8 sided Polygon =
Octagon
Hint: “oct”opus – 8 legs

11. Classifying Polygons by # of Sides
9 sided Polygon =
Nonagon
Hint: “Non” is similar to “Nine”

12. Classifying Polygons by # of Sides
10 sided Polygon =
Decagon
Hint: Think “Dec”ade (10 years

13. Classifying Polygons by # of Sides
Name 3
Triangle 4
Quadrilateral 5
Pentagon 6
Hexagon 7
Heptagon 8
Octagon 9
Nonagon 10
Decagon

14. Two Types of Polygons Convex – all vertices point outward
Concave – at least one vertex points inward towards the center of the polygon (The side looks like it “caved” in)

15. A Regular Polygon is a polygon in which all sides are the same length.
Regular Polygons
A Regular Polygon is a polygon in which all sides are the same length.
Equilateral Triangle 
 Square

16. Review of Similar Triangles
• 2 Triangles are similar if they have the same shape (i.e. the same angle in the same positions)

17. Similar Polygons
The same is true of polygons. 2 polygons are similar if they have the same angles in the same positions (i.e. same shape)
Similar Trapezoids 
^ Similar Pentagons ^
Similar Rectangles 

18. Other ways to Classify Polygons
Parallel Sides…
Reflex Angle …

19. Other ways to Classify
Polygons
Parallel Sides: Two lines on a plane that never meet. They are always the same distance apart.
Reflex Angle: An angle that is greater than 180 degrees

20. In-class Task…
On chart paper, draw a large Venn diagram with loops. Decide how you will label each loop. Choose from these attributes:
Regular
Quadrilateral
Parallel Sides
Irregular
Pentagon
Equal Sides
Triangle
Hexagon
Reflex Angle
Acute Angle
Right Angle
Obtuse Angle
Using the shapes provided, trace them into their appropriate categories