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Unit 8 - Lesson 16 - Grade 8: Illustrative Mathematics

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Last updated 2 months ago
7 Questions
Note from the author:
Grade 8 Unit 8
Lesson 16: When Is the Same Size Not the Same Size?
CC BY 2021 Illustrative Mathematics®
Grade 8 Unit 8
Lesson 16: When Is the Same Size Not the Same Size?
CC BY 2021 Illustrative Mathematics®

Three Figures (Warm Up)

1.

How are these shapes the same? How are they different?


A 4 : 3 Rectangle

A typical aspect ratio for photos is 4 : 3. Here’s a rectangle with a 4 : 3 aspect ratio.

2.

What does it mean that the aspect ratio is 4 : 3? Mark up the diagram to show what that means.

3.

If the shorter side of the rectangle measures 15 inches: What is the length of the longer side?

4.

If the shorter side of the rectangle measures 15 inches: What is the length of the rectangle’s diagonal?

5.

If the diagonal of the 4 : 3 rectangle measures 10 inches, how long are its sides?

6.

If the diagonal of the 4 : 3 rectangle measures 6 inches, how long are its sides?

The Screen Is the Same Size . . . Or Is It?

7.

Before 2017, a smart phone manufacturer’s phones had a diagonal length of 5.8 inches and an aspect ratio of 16 : 9. In 2017, they released a new phone that also had a 5.8-inch diagonal length, but an aspect ratio of 18.5 : 9. Some customers complained that the new phones had a smaller screen. Were they correct? If so, how much smaller was the new screen compared to the old screen?