7th Grade Math

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Slope

PART A B CDE

Multi-Part

Lesson 2

GLE 0706.3.6

Conceptualize the meanings

of slope using various

interpretations,

representations, and

contexts. SPI 0706.3.4

Interpret the slope of a line

as a unit rate given the

graph of a proportional

relationship. Also addresses

GLE 0706.1.5, GLE 0706.2.4,

SPI 0706.3.5.

392 Linear Functions

Main Idea

Identify constant rate

of change using tables

and graphs.

Vocabulary

rate of change

constant rate of change

nonlinear function

Constant Rate of Change

HEIGHTS The table shows Horacio’s height Age (yr) 912

at ages 9 and 12. Height (in.) 53 59

1. What is the change in Horacio’s height
   from ages 9 to 12?


2. Over what number of years did this change take place?


3. Write a rate that compares the change in Horacio’s height to the
   change in age. Express your answer as a unit rate and explain
   its meaning.

A rate of change is a rate that describes how one quantity changes in

relation to another. A rate of change is usually expressed as a unit

rate. A constant rate of change is the rate of change in a linear

relationship.

Use a Table

FUNDRAISING The table shows

+ 5

+ 5

+ 5

+ 40

+ 40

+ 40

Cars Washed

Number Money ($)

5 40

10 80

15 120

20 160

the amount of money a

booster club makes washing

cars for a fundraiser. Use

the information to find the

constant rate of change in

dollars per car.

Find the unit rate to determine the constant rate of change.

change in money

__

change in cars

= _40 dollars5 cars The money earned increases by $40 for every 5 cars.

= _8 dollars1 car Write as a unit rate.

So, the number of dollars earned increases by $8 for every

car washed.

a. PLANES The table shows the number of miles a plane traveled

while in flight. Use the information to find the constant rate of

change in miles per minute.

Time (min) 30 60 90 120

Distance (mi) 290 580 870 1,160

V

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