# Section 2-6 Rations and Proportions

```Section 2-6 Ratios and Proportions
Date: ____________________
Homework assignment: __________________________________________

A _____________ is a comparison of two numbers by division. They can be expressed in the
following ways:

The ratio of two measurements having different units of measure is called a ___________. A
________ that tells how many of one item is being compared to 1 of another item is called a
____________ ________.
Example:
If cheese costs \$2.54 for 8 slices, how much does one slice cost?
Example:
You are shopping for t-shirts. Which store offers the best deal?
Store A: \$25 for 2 shirts

Store B: \$45 for 4 shirts
Store C: \$30 for 3 shirts
An equation stating that two ratios are equal is called a _____________________.
Determine Whether Ratios Are Equivalent:
1.
6
2
,
10 5
2.
1
5
,
6 30
3.
10
5
,
42 21
There are names for terms in a proportion. In the example below, 4 and 10 are called the
___________________________, and 5 and 8 are called the _______________________ of the
proportion.
4:5 =
8 : 10
Means-Extremes Property of Proportion:
In a proportion, the _________________ of the extremes is equal to the ________________ of the means.

Basically, the above property allows us to use _______________________________ to determine if
two ratios form a proportion.
Cross-Products: Use cross-products to determine whether each pair of ratios forms a proportion.
15 35
,
1.
36 42

2.
7 42
,
3.
8 48
3
,
9
7 14
You can find the missing value in a proportion two ways:
o Using the
Property of Equality (What we did in Section 2-2)
o Using
Solve the Following Proportions:
𝑥
=
8
1.
25
40
2.
𝑥+4
5
=
3
8
3.
9𝑥−3
9
=
5𝑥+5
3
Setting up a Proportion: The gear on a bicycle is 8:5. This means that for every 8 turns of the pedals, the
wheel turns 5 times. Suppose the bicycle wheel turns about 2435 times during a trip. How many times
would you have to crank the pedals during the trip?

A rate called a ______________ is used to make a ____________ _______________ of something
too large or too small to be convenient at actual size.
Example: On a model airplane, the scale is 5 centimeters = 2 meters. If the model’s wingspan is 28.5
centimeters, what is the actual wingspan?
```