1. Objectives: SWBAT Classify polygons SWBAT determine the sum of the measures of the interior angles of a polygon SWBAT determine the measure of one interior angle of a regular polygon

2. Polygon – simple, closed figure formed by three or more line segments
Polygon – simple, closed figure formed by three or more line segments . Segments intersect only at endpoints. 1

3. 1 How are polygon’s classified? octagon decagon hexagon
By the number of sides they have
octagon
decagon
hexagon 1

4. 1 What are regular polygons?
A polygon that has all sides congruent and all angles congruent. 1

5. Determine whether the figure is a polygon
Determine whether the figure is a polygon. If it is, classify the polygon. If it is not a polygon, explain why.
The figure has 5 sides that only intersect at their endpoints.
Answer: It is a pentagon.

6. A B C D Classify the polygon. A. nonagon B. regular hexagon
C. Regular heptagon
D. regular pentagon A B C D

7. A B C D Which best describes the figure? A. hexagon; regular
B. hexagon; not regular
C. octagon; regular
D. octagon; not regular A B C D

8. A B C D Which best describes the figure? A. polygon; regular
B. cone; regular
C. quadrilateral; not regular
D. not a polygon A B C D

9. A B C D Which best describes the figure? A. hexagon; not regular
B. pentagon; not regular
C. pentagon; regular
D. not a polygon A B C D

11. Find the sum of the measures of the interior angles of a heptagon.
1260°
B °
C °
D °
Read the Test Item
The sum of the measures of the interior angles is (n – 2)180. Since a heptagon has 7 sides, n = 7.

12. Solve the Test Item
(n – 2)180 = (7 – 2)180 Replace n with 7.
= 5 ● 180 Simplify.
= 900 Multiply.
The sum of the measures of the interior angles of a heptagon is 900°.
Answer: The answer is C.

13. A B C D What is the sum of the interior angles of an octagon? A. 540°

14. A B C D What is the sum of the interior angles of a 25-gon ? A. 540°

15. TRAFFIC SIGNS A stop sign is a ___________ ___________.
What is the sum of the measures of the interior angles in a stop sign?
What is the measure of one interior angle in a stop sign?
Divide the sum by 8 to find the measure of one angle.
1080 ÷ 8 = 135
Answer: So, the measure of one interior angle in a stop sign is 135°.

16. A B C D Find the measure of each interior angle of a regular decagon.

17. PICNIC TABLE A picnic table in the park is a regular hexagon
PICNIC TABLE A picnic table in the park is a regular hexagon. What is the measure of one interior angle in the picnic table?
A. 720°
B °
C. 120°
D. 108° A B C D