1. 3.3 Day 1 - Interior Angles of Polygons
Essential Question: How can you find the interior angle measures of a polygon?

2. Vocabulary
Polygon: A closed figure with straight sides and doesn’t have lines cross through it.
Thumbs: Polygons (up) or Not Polygons (down)
Yes: polygon
Yes: polygon
No: not straight sides
No: not straight sides
No: sides cross

3. triangle 3 quadrilateral 4 pentagon 5 hexagon 6 heptagon 7 octagon 8
Sides
(n)
Polygon 3
triangle 4
quadrilateral
More than 10 sides:
n-gon
(n is # of sides) 5
pentagon
hexagon 7
heptagon 8
octagon 9
nonagon
decagon

4. a line segment which connects two non-adjacent vertices of a polygon
diagonal:
a line segment which connects two non-adjacent vertices of a polygon
Diagonal

5. Divide each polygon into triangles
There are 4 triangles.

6. Activity #1 a – f after completing front side, turn over and complete entire back side

8. What expression represents the sum of the interior angle measures of a polygon?
Interior angle measures of a 12-gon?

9. Vocabulary

10. Find the sum of the interior angle measures of a figure with 22 sides
Example 1
Your Turn – use what you learned:
Find the sum of the interior angle measures of a figure with 22 sides

11. Find the interior angle measures of this polygon
Example 2

12. Your Turn: Find x

13. Vocabulary
Regular Polygon: A polygon where all sides are congruent and all interior angles are congruent.
Thumbs: Regular Polygon (Up) or Not Regular (down) ( (
Not a regular polygon
Not a regular polygon
Regular polygon
Not a regular polygon

14. Example 3