lesson 5-1 ratios and percents. definition percent- a ratio that compares a number to 100

Lesson 5-1

Ratios and Percents

Definition

• Percent- A ratio that compares a number to 100.

Example 1

• POPULATION: According to the 2000 U.S. Census, 22 out of every 100 people living in West Virginia were younger than 18.

• Write the ratio as a percent

Example 2

• SPORTS: At a recent triathlon, 180 women competed for every 100 women who competed ten years earlier.

• Write the ratio as a percent

Write each ratio or fraction as a percent.

• POPULATION: According to the 2000 U.S. census, 13 out of every 100 people living in Delaware were 65 or older.

• BASEBALL: In 2001, Manny Ramirez got on base 40.5 times for every 100 times he was at bat.

Example 3

• CARS: About 1 out of 5 luxury cars manufactured in the United States is white.

• Write the ratio as a percent• Cross multiply to find x.

• x = 20%

Example 4

• TRAVEL: About of travelers use scheduled buses.

• Cross multiply to find x.

• x = 0.5 %

• TRANSPORTATION: About 4 out of 5 commuters in the United States drive or carpool to work.

• Find the percent.

• INTERNET: In 2000, about of the population in Peru used the internet.

• Find the percent.

Example 5• ENVIRONMENT: The circle graph shows an

estimate of the percent of each type of trash in landfills. Write the percent for paper and for plastic as a fraction in simplest form.

SCHEDULE: The table below shows an estimate of the percent of his day that Peter spends on each activity. Write the percent for eating and sleeping as fractions in simplest form.