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Unit 5 - Lesson 7 - Grade 8: Illustrative Mathematics

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13 Questions
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Grade 8 Unit 5
Lesson 7: Connecting Representations of Functions
CC BY 2021 Illustrative Mathematics®
Grade 8 Unit 5
Lesson 7: Connecting Representations of Functions
CC BY 2021 Illustrative Mathematics®
Lesson: Connecting Representations of Functions

Which are the Same? Which are Different? (Warm Up)

Here are three different ways of representing functions.

y = 2x


1.

How are they alike? How are they different?


Comparing Temperatures

The graph shows the temperature between noon and midnight in City A on a certain day.


The table shows the temperature, T, in degrees Fahrenheit, for h hours after noon, in City B.

2.

Which city was warmer at 4:00 p.m.?

3.

Which city had a bigger change in temperature between 1:00 p.m. and 5:00 p.m.?

4.

How much greater was the highest recorded temperature in City B than the highest recorded temperature in City A during this time?

5.

Compare the outputs of the functions when the input is 3.

Comparing Volumes

The volume, V, of a cube with edge length s cm is given by the equation V = s3.

The volume of a sphere is a function of its radius (in centimeters), and the graph of this relationship is shown here.

6.

Is the volume of a cube with edge length s = 3 greater or less than the volume of a sphere with radius 3?

7.

If a sphere has the same volume as a cube with edge length 5, estimate the radius of the sphere.

8.

Compare the outputs of the two volume functions when the inputs are 2.

It’s Not a Race (Optional)

Elena’s family is driving on the freeway at 55 miles per hour.

Andre’s family is driving on the same freeway, but not at a constant speed. The table shows how far Andre's family has traveled, d, in miles, every minute for 10 minutes.

9.

How many miles per minute is 55 miles per hour?

10.

Who had traveled farther after 5 minutes? After 10 minutes?

11.

How long did it take Elena’s family to travel as far as Andre’s family had traveled after 8 minutes?

12.

For both families, the distance in miles is a function of time in minutes.

Compare the outputs of these functions when the input is 3.

Cool Down: Comparing Different Areas

Comparing Different Areas

The table shows the area of a square for specific side lengths.


The area A of a circle with radius r is given by the equation A = π · r2.
13.

Is the area of a square with side length 2 inches greater than or less than the area of a circle with radius 1.2 inches?