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Learning Targets
- In a pair of figures, I can identify corresponding points, corresponding segments, and corresponding angles.
- I can describe what the scale factor has to do with a figure and its scaled copy.
Notes
Notes
Creating a scaled copy involves multiplying the lengths in the original figure by a scale factor. For example, to make a scaled copy of triangle ABC where the base is 8 units, we would use a scale factor of 4. This means multiplying all the side lengths by 4, so in triangle DEF, each side is 4 times as long as the corresponding side in triangle ABC.
Activities
Activities
3.2 Drawing Scaled Copies
3.2 Drawing Scaled Copies
Using the Geogebra Applet below ⇩ ⇩ ⇩
- Draw a scaled copy of either Figure A or B using a scale factor of 3.
- Draw a scaled copy of either Figure C or D using a scale factor of ½.
3.3 Which Operations? (Part 1)
3.3 Which Operations? (Part 1)
Diego and Jada want to scale this polygon so the side that corresponds to 15 units in the original is 5 units in the scaled copy.
Diego and Jada each use a different operation to find the new side lengths. Here are their finished drawings.
- What operation do you think Diego used to calculate the lengths for his drawing?
- What operation do you think Jada used to calculate the lengths for her drawing?
- Did each method produce a scaled copy of the polygon? Explain your reasoning.
3.3 Which Operations? (Part 2)
3.3 Which Operations? (Part 2)
Andre wants to make a scaled copy of Jada's drawing so the side that corresponds to 4 units in Jada’s polygon is 8 units in his scaled copy.
- Andre says “I wonder if I should add 4 units to the lengths of all of the segments?” What would you say in response to Andre? Explain or show your reasoning.
Lesson Summary
Lesson Summary
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