Chapter 6: Ratios, Proportions, and Percents

A ratio is

You can write a ratio in three ways:

1) as a fraction 2) as a quotient using a division sign 3) as a ratio using a colon

The table shows the results of a survey of seventh graders’ favorite ice cream flavors.

Use the table to find the following ratios in simplest form:

Flavor Number of Students Vanilla 55 Chocolate 180 Strawberry 95

a. The ratio of students who like strawberry to students who like chocolate

b. The ratio of students who like chocolate to total students

c. The ratio of students who like vanilla to students who do not like vanilla

1 Using Ratios to Express Unit Rates

A rate is a ratio that compares quantities in different units like miles per hour or price per gallon.

A Unit Rate has a denominator of 1 and can be used to compare best buys.

a. Find the unit rate (cost per ounce) for each size of apple juice.

Price Volume $0.72 16 oz $1.20 32 oz $1.60 64 oz

2 You try:

1) Two liters of spring water cost $1.98. What is the unit rate for the cost per liter?

2) A car goes 425 mi on 12.5 gallons of gas. What is the unit rate for miles per gallon?

3 Dimensional Analysis Review

When converting from one unit to another, it is often helpful to multiply by factors of one. This does not change the value of the original measurement, but it does convert the units.

a. Cole Hamels can pitch a baseball 90 miles per hour. Find this rate in feet per second.

b. You want purchase ribbon for $3 per yard. What is the price per inch of the ribbon?

4 Homework: Book 290; 1‐11 odd; 13‐22; 27‐28; 30‐31; 39‐45

Optional: 32 ‐ 33

5