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Geo 72 Lesson with notes 1st a.notebook 1 February 25, 2016 Feb 118:39 PM 72 Similar Polygons Learning Targets: I can use proportions to identify similar polygons. I can solve problems using the properties of similar polygons In what direction has the picture been stretched? Why is the photo distorted when it is made to fit the screen? What other ways could the picture be used to fit the screen without distorting it? Feb 118:43 PM Similar polygons: have the same shape but not necessarily the same size.
Transcript of 72 Similar Polygons - PC\|MACimages.pcmac.org › ... › Uploads › Forms ›...
Geo 72 Lesson with notes 1st a.notebook
1
February 25, 2016
Feb 118:39 PM
72 Similar Polygons
Learning Targets:I can use proportions to identify similar polygons.I can solve problems using the properties of similar polygons
In what direction has the picture been stretched?
Why is the photo distorted when it is made to fit the screen?
What other ways could the picture be used to fit the screen without distorting it?
Feb 118:43 PM
Similar polygons: have the same shape but not necessarily the same size.
Geo 72 Lesson with notes 1st a.notebook
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February 25, 2016
Feb 118:45 PM
Remember congruence statements, the order of vertices in a statment is important because it identifies corresponding angles and sides.
Same with similarity statements, they must be in order of corresponding angles and sides.
Feb 118:47 PM
Example 1:
1. If ΔABC ΔRST, list all pairs of congruent angles and write a proportion that relates the corresponding sides.
Geo 72 Lesson with notes 1st a.notebook
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February 25, 2016
Feb 118:52 PM
2. In the diagram, NPQR UVST. List all pairs of congruent angles, and write a proportion that relates the corresponding sides.
Feb 177:46 AM
Geo 72 Lesson with notes 1st a.notebook
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February 25, 2016
Feb 177:51 AM
Feb 118:55 PM
Scale factor: ratio of the lengths of the corresponding sides of two similar polygons
In the diagram, ΔABC ΔXYZ
The scale factor of ΔABC to ΔXYZ is 6/3 or 2.
The scale factor of ΔXYZ to ΔABC is 3/6 or 1/2.
Geo 72 Lesson with notes 1st a.notebook
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February 25, 2016
Feb 118:59 PM
Feb 119:01 PM
Example 2:
3. Tan is designing a new menu for the restaurant where he works. Determine whether the following sizes for the new menu are similar to the original menu. If so, write the similarity statement and scale factor. Explain your reasoning.
Geo 72 Lesson with notes 1st a.notebook
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February 25, 2016
Feb 178:48 AM
Feb 119:05 PM
4. Determine whether the triangles shown are similar. If so, write the similarity statement and scale factor. Explain your reasoning.
Geo 72 Lesson with notes 1st a.notebook
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February 25, 2016
Feb 119:08 PM
Feb 119:09 PM
Example 3: The two polygons are similar.
5. Find x.
6. Find y.
Geo 72 Lesson with notes 1st a.notebook
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February 25, 2016
Feb 119:11 PM
Find the value fo each variable if ΔJLM ΔQST.
7. Find x.
8. Find y.
Feb 119:14 PM
In similar polygons, the ratio of any two corresponding lengths is proportional to the scale factor between them.
Geo 72 Lesson with notes 1st a.notebook
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February 25, 2016
Feb 119:33 PM
Feb 119:39 PM
Example 4:
9. If ABCDE RSTUV, find the scale factor of ABCDE to RSTUV and the perimeter of each polygon.
Geo 72 Lesson with notes 1st a.notebook
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February 25, 2016
Feb 119:41 PM
10. If MNPQ XYZW, find the scale factor of MNPQ to XYZW and the perimeter of each polygon.
