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Proportions

PART A B CDE

Multi-Part

Lesson 1

GLE 0706.2.3

Develop an understanding of

and apply proportionality.

GLE 0706.2.4 Use ratios,

rates and percents to solve

single- and multi-step

problems in various contexts.

Also addresses SPI 0706.2.7.

266 Proportions and Similarity

Main Idea

Determine unit rates.

Vocabulary

rate

unit rate

Rates

Choose a partner and take each

other’s pulse for 2 minutes.

1. Count the number of beats for each of
   you.


2. Write the ratio beats to minutes as a
   fraction.

A ratio that compares two

160 beats

_

2 minutes

quantities with different^

kinds of units is called a rate.

The units beats and

minutes are different.

When a rate is simplified so

80 beats

_

1 minute

that it has a denominator of^

1 unit, it is called a unit rate.

The denominator

is 1 unit.

The table below shows some common unit rates.

Rate Unit Rate Abbreviation Name

__number of miles

1 hour^ miles per hour mi/h or mph average speed

__number of miles

1 gallon^ miles per gallon mi/gal or mpg gas mileage

__number of dollars

1 pound^ price per pound dollars/lb unit price

Find a Unit Rate

BIKING Adrienne biked 24 miles in 4 hours. If she biked at a

constant speed, how many miles did she ride in one hour?

24 miles in 4 hours = _24 mi

4 h

Write the rate as a fraction.

= _24 mi ÷^4

4 h ÷ 4

Divide the numerator and the denominator by 4.

= _6 mi

1 h

Simplify.

Adrienne biked 6 miles in one hour.

Find each unit rate. Round to the nearest hundredth if necessary.

a. $300 for 6 hours b. 220 miles on 8 gallons

V

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