1. Pretest Please complete the pretest for this standard
on your own. Try to remember all you can from
our first discussion of this topic.
Day 1
The pretest can be found online at The teacher and student logins are the same as FCAT Explorer. If you have access to computers, you may wish to have your students complete this assessment online. Using the paper/pencil copy and a bubble answer sheet from Performance Matters will give you automatically graded assessment and valuable data for immediate use.

2. Determine the measures of interior and exterior angles of polygons, justifying the method used.
MA.912.G.2.2

3. LEQ: How do you find the sum of the measures of the interior and exterior angles of a polygon?
Vocabulary: Match each term with the picture
that best describes it.
Equilateral Polygon
Equiangular Polygon
Regular Polygon
Polygon Interior Angle Sum Theorem
Polygon Exterior Angle Sum Theorem
Vocab should be interactive when possible.

4. I do… Example 1: What is the measure of the exterior angle shown?
First, recall the triangle exterior angle theorem:
The exterior angle is equal to the sum of the two non-adjacent interior angles.
(X+10)
Set up an equation.
(x + 10) + (2x + 40) = (4x + 20)
(2X+40)
(4X+20)
Combine like terms and solve for x.
3x + 50 = 4x + 20
Day 2
50 = x + 20
30 = x
4(30) + 20
=140

5. I do…
Example 2: Sunny is drawing a regular polygon. She has drawn two of the sides with an interior angle of 135°, as shown below. How many sides will the regular polygon have when Sunny completes her drawing?
First, recall how to find the interior angle of a regular polygon.
135°
where n = number of sides
Now set up the equation to find n when you know the angle measure.
Solve for n.
Day 2

6. I do… Example 3: Find the value of x in the hexagon below.
First, Find the angle sum of a hexagon.
2x+9
3x+4
Angle Sum =180(n-2) where n=6
= 180(6-2)
= 180(4) = 720 4x
3x+2
Now write an equation stating the sum of the angles is equal to 720.
(2x+9) + (3x+4) + (3x+2) + (5x+2) + (5x+1) + (4x) = 720
5x+1
5x+2
Combine like terms and solve for x.
Day 2
26x + 18 = 720
26x = 702
x = 27

7. We do…
Sage and Scribe
Day 3 and 4
Low to Moderate DOK
Sage and Scribe

8. We do… Shoulder Partner
Think of a regular polygon over 4 sides and find the measure of an interior angle using the angle sum theorem.
Write the measure of the interior angle on your partner’s paper and have them prove which polygon you chose.
Pass back the paper to its owner and coach or praise your partner’s work.
Day 3 and 4
Moderate/High DOK

9. 2.Each problem has an error. Find the error and correct it.
You do…
2.Each problem has an error. Find the error and correct it.
1. Find the value of x.
3. John is drawing a regular polygon. He has drawn two sides with an exterior angle measure of 72°, as shown below. When he completes her regular polygon, what will be the sum, in degrees, of the measures of the interior angles?
All three questions.
72°

10. You do…
1. Find the value of x.
All three questions.
Answer: x = 100

11. 2.Each problem has an error. Find the error and correct it.
You do…
2.Each problem has an error. Find the error and correct it.
All three questions.
Answer: You should use 180(n-2) for angle sum.
Answer: You did not include both 130’s in your angle sum.

12. You do…
3. John is drawing a regular polygon. He has drawn two sides with an exterior angle measure of 72°, as shown below. When he completes her regular polygon, what will be the sum, in degrees, of the measures of the interior angles?
72°
All three questions.
Answer: 540

13. Post Test
Please complete the post test for this standard on your own. Do the best you can, hopefully you will show improvement over your pretest score.
Day 6
The post test can be found online at The teacher and student logins are the same as FCAT Explorer. If you have access to computers, you may wish to have your students complete this assessment online. Using the paper/pencil copy and a bubble answer sheet from Performance Matters will give you automatically graded assessment and valuable data for immediate use.