A comparison of two quantities
 Often expressed as a fraction



The ratio of the age of a 34 year old
parent to that of a 10 year old child is
34 to 10
Also can be written as:
34: 10
 34
10


3.4
An equation that states that two
ratios are equal
 Examples:

2 6

3 9
x 2

24 3

To solve proportions, we will
cross multiply

Example:
x 2

63 9

Example:
65 13

10 x

Example:
3 12

5 y

Example:
1 x

2 5
The property tax on a house is $8 per
$1000 assessed valuation. What is the
tax on a house assessed at $165,000?
A certain car can travel 180 miles on 8
gallons of gasoline. How far can this
car travel on 19 gallons of gasoline?
The scale on a map says that 0.5 cm
represents 25 km. On the map the
measurement between two cities is 5 cm.
What is the actual distance between the
cities?
Pg. 150 #’s 2 – 16 even; 25 - 29