Ratio
11-1
Each form is read as
“the ratio of a tob.”
A ratio is a way of comparing two numbers or
quantities, aand b, by division. The numbers,
aand b, are called the terms of the ratio.
A ratio can be written in three forms.
Word form: ato b
Ratio form: a: b
Fraction form:
You can write a ratio to compare two amounts—
a part to a part, a part to a whole, or the whole to a part.
The picture above shows the following ratios:
a
b
Use the bar graph. Write each ratio in three ways.
- news magazines to sports magazines
- home magazines to fashion magazines
- all magazines to home magazines
- sports and hobby magazines to all magazines
Number
Hobby
Home
Fashion
Sports
News
10 2 3 4 5
Magazines
Magazines at
Anita's Newsstand
You can simplify ratios by dividing 2 to 20
both terms by their greatest 2 2 to 20 2
common factor (GCF). 1 to 5 Simplify.
Type Comparisons Word Ratio Fraction
Form Form Form
part to part 3 to 5 3 : 5
3
5
part to whole 2 to 10 2 : 10
1
2
0
whole to part 10 to 3 10 : 3
10
3
the number of fashion magazines
to the number of news magazines
the number of sports magazines to
the total number of magazines
the total number of magazines to
the number of fashion magazines
Divide terms by 2.
1.2
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