Unit 1, Lesson 3
Making Scaled Copies
Grade 7
Preparation
Lesson Narrative
In this lesson, students draw scaled copies of simple shapes, applying what they have learned about corresponding parts and scale factor. They strengthen their understanding that the relationship between scaled copies is multiplicative, not additive. Students make careful arguments about the scaling process (MP3) and have opportunities to use tools like tracing paper or index cards strategically (MP5).
As students draw scaled copies and analyze scaled relationships more closely, encourage them to continue using the terms scale factor and corresponding in their reasoning.
Math Community
In this lesson, students review the themes that arose when they shared their initial thoughts in Exercise 1 about what they think it should look like and sound like to do math together as a community. Students then have a chance to both affirm and add to the ideas that were generated.
- Critique (orally and in writing) different strategies (expressed in words and through other representations) for creating scaled copies of a figure.
- Draw a scaled copy of a given figure using a given scale factor.
- Generalize (orally and in writing) that the relationship between the side lengths of a figure and its scaled copy is multiplicative, not additive.
Let’s draw scaled copies.
Required Preparation
For the digital version of the activity, acquire devices that can run the applet.