Transcript Document 648728

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
22
= 22%
100
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
180
= 180%
100
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.
1 x(percent)
=
5
100
• x = 20%
Example 4
1
200
• TRAVEL: About
of travelers use
scheduled buses.
• Cross multiply to find x.
1
x(percent)
=
200
100
• x = 0.5 %
• TRANSPORTATION: About 4 out of 5
commuters in the United States drive or
carpool to work.
• Find the percent.
3
• INTERNET: In 2000, about
of the population in
200
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.
30
3
Paper : 30% =
or
100 10
24
6
Plastic : 24% =
or
100 25
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.
5
1
Eating : 5% =
or
100 20
35
7
Sleeping : 35% =
or
100 20