Unit 2, Lesson 11
More Dilations
Accelerated 7
11.1
Warm-up
11.2
Activity
Your teacher will give you either a problem card or a data card. Do not show or read your card to your partner.
If your teacher gives you the problem card:
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Silently read your card, and think about what information you need to answer the question.
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Ask your partner for the specific information that you need. “Can you tell me ?”
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Explain to your partner how you are using the information to solve the problem. “I need to know because . . . .”
Continue to ask questions until you have enough information to solve the problem.
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Once you have enough information, share the problem card with your partner, and solve the problem independently.
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Read the data card, and discuss your reasoning.
If your teacher gives you the data card:
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Silently read your card. Wait for your partner to ask for information.
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Before telling your partner any information, ask, “Why do you need to know ?”
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Listen to your partner’s reasoning and ask clarifying questions. Only give information that is on your card. Do not figure out anything for your partner!
These steps may be repeated.
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Once your partner says they have enough information to solve the problem, read the problem card, and solve the problem independently.
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Share the data card, and discuss your reasoning.
Student Lesson Summary
One important use of coordinates is to communicate geometric information precisely. Like an address in a city, they tell you exactly where to go. Because the plane is laid out in a grid, these “addresses” are simple, consisting of 2 signed numbers.
Consider a quadrilateral in the coordinate plane. Performing a dilation of requires 3 vital pieces of information:
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The coordinates of , , , and
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The coordinates of the center of dilation
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The scale factor
With this information, we can dilate each of the vertices , , , and and then draw the corresponding segments to find the dilation of . Without coordinates, describing the location of the new points would likely require sharing a picture of the polygon and the center of dilation.
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