Download 6-2 Polygons 2016.notebook

6­2 Polygons 2016.notebook
January 05, 2017
Daily Do from last class
64
o
Homework Answers 6­1:
1. 60o 2. 119o 3. 35o 4. 140o 5. 10o 6. 82o 8. 121o 7. 68o 9. 174o 10. 91o 11. 46o 12. 75o 13. 43o Vertical angles
14. 43o Alternate Exterior Angles
15. 66o 16. 151o Lesson 6­2
Polygons
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6­2 Polygons 2016.notebook
January 05, 2017
Polygons
­a sequence of line segments placed end to end to form a simple closed figure.
NOT POLYGONS... figures that curve, are open, or overlap.
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6­2 Polygons 2016.notebook
January 05, 2017
Regular polygon
­a polygon who sides are equivalent (all sides congruent) and who angles are equiangular (all angles congruent).
Angles of Polygons
How do we find the number of degrees in any polygon?
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6­2 Polygons 2016.notebook
January 05, 2017
Any triangle is ___________________ degrees.
If you divide a polygon into triangles you will discover how many degrees are in that polygon.
A quadrilateral equals ____________________
• Choose any vertex. • Draw a straight line from that vertex to another vertex. (Repeat if possible)
• How many triangles can you make?
Click Square for Video
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6­2 Polygons 2016.notebook
January 05, 2017
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A quadrilateral equals ____________________
360
When you divide a quadrilateral into triangles, you can make two triangles. 2 X 180 = 360
A pentagon equals ____________________
• Choose any vertex. • Draw a straight line from that vertex to another vertex. (Repeat if possible)
• How many triangles can you make?
Click Pentagon for Video
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6­2 Polygons 2016.notebook
January 05, 2017
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540
A pentagon equals ____________________
When you divide a pentagon into triangles, you can make three triangles. 3 X 180 = 540
A hexagon equals ____________________
Click Hexagon for Video
• Choose any vertex. • Draw a straight line from that vertex to another vertex. (Repeat if possible)
• How many triangles can you make?
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6­2 Polygons 2016.notebook
January 05, 2017
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720
A hexagon equals ____________________
When you divide a hexagon into triangles, you can make four triangles. 4 X 180 = 720
A heptagon equals ____________________
Click Heptagon for Video
• Choose any vertex. • Draw a straight line from that vertex to another vertex. (Repeat if possible)
• How many triangles can you make?
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6­2 Polygons 2016.notebook
January 05, 2017
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900
A heptagon equals ____________________
When you divide a heptagon into triangles, you can make five triangles. 5 X 180 = 900
Have you noticed
a pattern?
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6­2 Polygons 2016.notebook
January 05, 2017
Number of Number of Sum of Angles
sides
Triangles
Name of polygon
Triangle
3
1
1 X 180 = 1800
4
2
2 X 180 = 3600
5
3
3 X 180 = 6
4
4 X 180 = 7
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9
10
n­gon
The Interior Angle Sum
To find the total number of degrees in any polygon: (N­2) 180
number of sides
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6­2 Polygons 2016.notebook
Find the measure of AN interior angle of a polygon.
January 05, 2017
Formula:
sum of angles
number of angles
regular pentagon?
regular nonagon?
regular 13­gon?
Exit Question
Find the measure of one interior angle of a regular 38­gon.
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6­2 Polygons 2016.notebook
Name of polygon
Triangle
January 05, 2017
Number of Number of Sum of Angles
sides
Triangles
3
1
1 X 180 = 1800
4
2
2 X 180 = 3600
5
3
3 X 180 = 6
4
4 X 180 = 1 Interior angle of a regular polygon
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8
9
10
n­gon
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Attachments
quad.wmv
pentagon.wmv
hexagon.wmv
heptagon.wmv