PSSA 1.7 Ratio and Proportion
Ratio: a comparison to two numbers by division
A to B
A:B
A
B
We use ratios to describe rates such as miles/hour, feet/sec, (number correct)/total, $/hour,
$/pound, $/acre.
Proportion: a statement that two ratios are equal.
5miles 30miles
=
1hour
6hours
Ex 1
In a class of 25 students, there are 7 boys. What is the ratio of girls to boys?
Ex 2
A field goal kicker successfully completes 4/5 field goal attempts. How many successful kicks would he have
if he attempted 225 kicks?
How many kicks would he have to attempt to successfully kick the ball 108 times?
Ex 3
If the grocery is selling 3 cases of soda for $8.00, how much will it cost to purchase 15 cases?
Ex 4
It costs $4.59 for 12 ounces of a particular pool chemical. How much would you pay for 80 ounces of the
chemical?
Ex 5
In a recipe, you need 2 ½ cups of flour to make 3 dozen cookies. How much flour would be required to make
10 dozen cookies?
Ex 6
The scale for an architect’s drawing is 1in:5ft. A room on the drawing measures 3.25 inches x 4.75 inches.
How many feet would that represent?
Ex 7
Which is a better salary offer?
$25.97 per hour for 40 hours
or $975.00 per week (also a 40 hour work week)
Ex 8
Solve the proportions.
x 60
=
5 180
27 x
=
82 4
1. 5 x
=
25 75
Homework: p. 17-18 (1-15) Open Ended question 11.11