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Module 8.3 Lesson 3 Examples of Dilations.notebook
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May 24, 2016
5/24/25Lesson #33: Examples of DilationsHW: Page 19 #35 and CRS 18 due tomorrow
Do now:Complete Page 12 #2 using O as the center (not O`)
Module 8.3 Lesson 3 Examples of Dilations.notebook
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May 24, 2016
How many points would you need to separate the circle into to draw an accurate dilated image? Page 15
Use Compass
Module 8.3 Lesson 3 Examples of Dilations.notebook
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May 24, 2016
How many points would you need to separate the circle into to draw an accurate dilated image? Page 15Use Compass
9°
160
Module 8.3 Lesson 3 Examples of Dilations.notebook
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May 24, 2016
How many points would you need to separate the circle into to draw an accurate dilated image? Page 15
0°135
Module 8.3 Lesson 3 Examples of Dilations.notebook
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Would you be able to produce a circle as an image from the number of points used in this example?
Page 15
Module 8.3 Lesson 3 Examples of Dilations.notebook
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What's wrong with using these points?
Module 8.3 Lesson 3 Examples of Dilations.notebook
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What about this image. Does it look like a circle?
Module 8.3 Lesson 3 Examples of Dilations.notebook
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The number of points to dilate that is enough is as many as are needed to produce a dilated image that looks like the original. For curved figures, like this circle, the more points you dilate the better. The location of the points you choose to dilate is also
important.
Module 8.3 Lesson 3 Examples of Dilations.notebook
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What can we do to map this new triangle, triangle A'B'C', back to the original triangle? Be as specific as possible!
Page 17
Module 8.3 Lesson 3 Examples of Dilations.notebook
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Reverse a dilation by using a scale factor that
is the multiplicative inverse (reciprocal) of the first scale
Module 8.3 Lesson 3 Examples of Dilations.notebook
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Original Dilation scale factor: 2Scale factor to reverse the dilation:
Original Dilation scale factor: 17
Scale factor to reverse the dilation:
Original Dilation scale factor: 23
Scale factor to reverse the dilation:
Module 8.3 Lesson 3 Examples of Dilations.notebook
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May 24, 2016
Step 1- Measure the distances between point O and A and point O and A'.
|OA| = 6 units|OA'| = 2 units
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58°
Module 8.3 Lesson 3 Examples of Dilations.notebook
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May 24, 2016
Step 2- Compare the distances and create an equation! You want to now go from A' to A.
|OA| = 6 units|OA'| = 2 units
Think!!! What can I multiply |OA'| by to give me |OA|.
Module 8.3 Lesson 3 Examples of Dilations.notebook
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May 24, 2016
If a figure is dilated by scale factor, r, to bring the dilated figure back to the original size, we must dilate it by a scale factor of .
If a scale factor is r =6, then the bring a dilated figure back to the original size, the scale factor must equal ________.
(reciprocal)