Ratios and Rates

Mrs. Kuznia

Math 8

Day 5

Brainpop

• http://www.brainpop.com/math/ratioproportionandpercent/ratios/

What is a ratio?

• A ratio is a comparison of two quantities measured in the same units.

• Ratios must always be written in simplest form!!!!

RATIOS

Ratios can be written, or expressed, three different ways.

1. 3 to 42. 3:43. 3

4

RATIOS

There are 3 green aliens and 4 purple

aliens. The ratio of

green aliens to

purple aliens is

3 to 4.

RATIOS

The ratio of green aliens to total aliens is 3 to 7. The ratio of

total aliens to purple

aliens is 7 to 4.

RATESA rate is a ratio that compares quantities that

are measured in different units.

.

Example

This spaceship travels at a certain speed.

Speed is an example of a rate.

Speed can be measured in many different ways.

This spaceship can travel 100 miles in 5 seconds. 100 miles in 5 seconds is a rate.

RATES

Rates are often written in fraction form.100 miles in 5 seconds is a rate.It can be written as…..

5

100 Miles

Seconds

RATES

One key word that often identifies a rate is PER.Miles per gallon, Points per free throw,Dollars per pizza, Sticks of gum per pack

What other examples of rates can your group think of?