1. Polygons
Subtitle

2. Polygon Names What is a polygon? What is a regular polygon?
What does it mean to be conCAVE?
What does it mean to be conVEX?

3. Can you list the names of the following polygons?
Number of Sides
Polygon Name 3 4 5 6 7
Number of Sides
Polygon Name 8 9 10 11 12

4. Polygon Practice
Name the polygon, whether it is regular, whether it is concave or convex?

5. Polygon Angles How many triangles are How many triangles are
in the polygon?
How many degrees are in a triangle?
How many degrees are the interior angles?
How many triangles are
in the polygon?
How many degrees are in a triangle?
How many degrees are the interior angles?

6. Polygon Angles Continued
How many triangles are
in the polygon?
How many degrees are in a triangle?
How many degrees are the interior angles?

7. Equations
Can we come up with an equation that gives the sum of the interior angles of a n-gon based on the number of sides?
Remember every equation must have a variable and an equal sign.

8. Exterior angles What is the measure of each interior angle?
What is the measure of each exterior angle?
What is the sum of the exterior angle?

9. Exterior Angles Continued
What is the measure of each interior angle?
What is the measure of each exterior angle?
What is the sum of the exterior angle?

10. Exterior Angles Continued
What is the measure of each interior angle?
What is the measure of each exterior angle?
What is the sum of the exterior angle?
What is the equation for
the sum of the exterior angles?

11. These equations only work when the polygons are REGULAR
WARNING!!!
These equations only work when
the polygons are REGULAR

12. Practice
Assuming all shapes are regular polygons find the sum of the interior angles. Find the sum of the exterior angles.
Find the measure of one interior angle and one exterior angle.

13. Practice
Do not assume they are regular pentagons. If they are regular find the sum of the interior and exterior angles.
Heptagon concave octagon regular decagon
Regular 18-gon regular convex 50-gon regular 94-gon

14. More practice
The sum of the interior angles of a shape is 2700 assuming it is a regular polygon how many sides does it have?
Assuming a polygon is a regular polygon and it has an interior angle measure of 175 degrees how many sides does it have?
Assuming a polygon is a regular polygon if an exterior angle is 10 degrees how many sides does the polygon have?