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R. Getso
6.1 Ratio and Proportion
Writing Ratio as Fractions
A ratio is the quotient of two quantities.
For example, a percent can be thought of as a ratio, since it is the quotient of a number and 100.
53% =
or the ratio of 53 to 100.
The ratio of a number a to a number b is their quotient. Ways of writing ratios are:
a to b,
a : b, and
Examples: Write the ratio in lowest terms.
1. 6 hours to 36 hours
2. 36 minutes to 3 hours
Solving Proportions
A proportion is a statement that two ratios are equal.
If
and
are ratios, then
=
is a proportion.
3. 17¢ to $4
Math 100 Class Notes
Example:
4. Is
=
a true proportion?
Examples: Solve each proportion.
5.
=
6.
=
7.
=
8. A 16-oz Cinnamon Mocha Iced Tea at a
local coffee shop has 80 calories. How many
calories are there in a 28-oz Cinnamon Mocha
Iced Tea?
Helpful Hint: When writing proportions to solve problems, write the proportions so that the
numerators have the same unit measures and the denominators have the same unit measures.
For example,
2 inches 7 inches
=
5 miles
miles
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