Unit 1, Lesson 1
What Are Scaled Copies?
Grade 7
1.1
Warm-up
Printing Portraits
Here is a portrait of a student.
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Look at Portraits A–E. How is each one the same as or different from the original portrait of the student?
- Some of the Portraits A–E are scaled copies of the original portrait. Which ones do you think are scaled copies? Explain your reasoning.
- What do you think “scaled copy” means?
1.3
Activity
Pairs of Scaled Polygons
Your teacher will give you a set of cards that have polygons drawn on a grid. Mix up the cards and place them all face up.
- Take turns with your partner to match a polygon with another polygon that is a scaled copy.
- For each match you find, explain to your partner how you know it’s a match.
- For each match your partner finds, listen carefully to their explanation. If you disagree, discuss your thinking and work to reach an agreement.
- When you agree on all of the matches, check your answers with the answer key. If there are any errors, discuss why and revise your matches.
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Select one pair of polygons to examine further. Explain or show how you know that one polygon is a scaled copy of the other. You can draw both polygons on the grid if it helps.
Student Lesson Summary
What is a scaled copy of a figure? Let’s look at some examples.
The second and third drawings are both scaled copies of the original Y.
However, here, the second and third drawings are not scaled copies of the original W.
3 drawings of the letter W. The second drawing is spread out making it wider and shorter than the first drawing. The third drawing is squished in, making it narrower, but the same height as the the original drawing.
The second drawing is spread out (wider and shorter). The third drawing is squished in (narrower, but the same height).
We will learn more about what it means for one figure to be a scaled copy of another in upcoming lessons.
scaled copy
A scaled copy is a copy of a figure where every side length in the original figure is multiplied by the same number.
Triangle