# Lesson 5 1

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```					 5-1 Ratios

California
Standards
NS1.2 Interpret and use ratios in
different contexts (e.g., batting
averages, miles per hour) to show the
relative sizes of two quantities, using
appropriatea
notations ( b , a to b, a:b).

Holt CA Course 1
5-1 Ratios

Vocabulary
ratio

Holt CA Course 1
5-1 Ratios

baskets in 25 attempts. She compared the
number of attempts she made by using the
17
ratio 25 . A ratio is a comparison of two
numbers or quantities.

to attempts in three different ways.

17      17 to 25         17:25
25

Holt CA Course 1
5-1 Ratios
Twenty students are asked to choose their
favorite music category. Eight chose pop, seven
chose hip hop, and five chose rock. Write each
ratio in all three forms.

rock to hip hop
rock = 5         There are 5 who choose rock
hip hop  7         and 7 who choose hip hop.

The ratio of rock to hip hop can be written
5
as , 5 to 7, 5:7.
7

Holt CA Course 1
5-1 Ratios
Twenty students are asked to choose their
favorite music category. Eight chose pop, seven
chose hip hop, and five chose rock. Write each
ratio in all three forms.

hip hop to pop

hip hop = 7       There are 7 who choose hip
pop     8       hop and 8 who choose pop.

The ratio of hip hop to pop can be written
7
as , 7 to 8, 7:8.
8

Holt CA Course 1
5-1 Ratios
Twenty students are asked to choose their
favorite music category. Eight chose pop, seven
chose hip hop, and five chose rock. Write each
ratio in all three forms.

rock to pop and hip hop
rock   t= 5      There are 5 who choose rock,
pop & hip hop 15      8 who choose pop, and 7 who
choose hip hop.
The ratio of rock to pop and hip hop can
5 , 5 to 15, 5:15.
be written as
15

Holt CA Course 1
5-1 Ratios

Sometimes a ratio can be simplified. To
simplify a ratio, first write it in fraction
form and then simplify the fraction.

Holt CA Course 1
5-1 Ratios

Remember!
A fraction is in simplest form when the
GCD of the numerator and denominator
is 1.

Holt CA Course 1
5-1 Ratios
Additional Example 2: Writing Ratios in Simplest
Form
in 3 minutes. Write the ratio of words to minutes in
words = 600         Write the ratio as a fraction.
minutes   3
words = 600 ÷ 3     Simplify.
minutes   3÷3
words = 200         For every minute, there are
The ratio of words to minutes is 200 to 1.

Holt CA Course 1
5-1 Ratios

To compare ratios, write them as
fractions with common denominators.
Then compare the numerators.

Holt CA Course 1
5-1 Ratios
Honey-lemon cough drops come in packages of 30
drops per 10-ounce bag. Cherry cough drops come in
packages of 24 drops per 6-ounce bag. Tell which
package has the greater ratio of drops to ounces.
Honey-lemon      Cherry
Drops            30            24
Ounces           10            6

drops = 30 = 3       Write the ratios as
Honey-lemon:
ounces   10   1       fractions with
drops = 24 = 4       common
Cherry:
ounces   6    1       denominators.

Because 4 > 3 and the denominators are the same, the drops
to ounces is greater in the bag of cherry cough drops.

Holt CA Course 1
5-1 Ratios
Check It Out! Example 1A
Nineteen students are asked to choose their
favorite sport. Nine chose rock climbing, four
chose kite surfing, and six chose snow boarding.
Write each ratio in all three forms.

snow boarding to rock climbing

snow boarding = 6    There are 6 who choose snow
rock climbing  9    boarding and 9 who choose
rock climbing.
The ratio of snow boarding to rock climbing
6
can be written as , 6 to 9, 6:9.
9

Holt CA Course 1
5-1 Ratios
Check It Out! Example 2
At Casitas Middle School, there are 456 microscopes
for 152 students. Write the ratio of microscopes to
simplest form.
microscopes = 456            Write the ratio as a
students     152            fraction.
microscopes = 456 ÷ 152     Simplify.
students     152 ÷ 152
microscopes =    3          For every microscope,
students        1          there are 3 students.
The ratio of microscopes to students is 3 to 1.

Holt CA Course 1
5-1 Ratios
Check It Out! Example 3
Mixed nuts come in small packages of 25 per 5 ounce package
and large packages of 56 per 8 ounce package. Tell which bag
has the greater ratio of mixed nuts per ounce.

Large          Small
Mixed nuts            56          25
Ounces                8           5

Large:
mixed nuts   = 56 = 7     Write the ratios as
ounces        8    1     fractions with
mixed nuts                common
Small:                  = 25 = 5
ounces        5    1     denominators.

Because 7 > 5 and the denominators are the same, the large
package has the greater ratio of mixed nuts to ounces.

Holt CA Course 1

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