1. Area of Regular Polygons

2. We will determine the area of regular polygons using notes.

3. Copy onto your notes:

4. Regular Polygon a = apothem P = perimeter equal sides equal angles * Use this formula for regular pentagons, hexagons, octagons, etc. Copy onto your notes:

5. Apothem apothem - connects center to midpoint and forms a right angle Copy onto your notes:

6. ExamplesNon-Examples Copy onto your notes:

8. Example 2 : Find the area of the regular octagon. 2.5 cm 14 cm You try this one now…

9. First, divide the hexagon into 6 six congruent figures. Now, divide the hexagon into 12 congruent figures. What figures did you create? Equilateral Triangles What figures did you create? 30 – 60 – 90 Triangles Label the sides of one of the 30 – 60 – 90 Triangle. What did you label the apothem? x√3 What represents the side length? 2x Click through the animation and copy down the important information.

10. Copy onto your notes:

11. Example 4: Find the area of the regular hexagon with a perimeter 42 cm. (Round to the nearest tenth) You try this one now…

12. Example 5 : The area of a regular hexagon is 54 cm 2. If the perimeter of the hexagon is 48 cm, what is the length of the apothem? Keep trying!

13. Example 6: The area of a regular nonagon is 198 mm 2. If the apothem of the figure is 6 mm, what is the perimeter? Keep trying!

14. Example 7: The area of regular pentagon ABCDE is 92 cm 2. If the apothem of the figure is 4 cm, what is the length of CD? A B C D E Keep trying!