1. Today’s Objective
To be able to use ratios and relate quantities in the same units.

2. Suppose…..
You had two U.S. coins that total 55 cents. One of the coins is not a nickel, what are the two coins?

3. Suppose…..
That you were riding in the back seat of a car that was traveling on I-10 and you wanted to determine the speed of the car without looking at the speedometer. Is this possible?

4. Yes… Speed is determined by How many miles traveled in an hour
Step 1.. Find out, in seconds, how long it takes to travel between any two mile markers (distance is 1 mile).
Step Determine how many seconds in an hour.
1 hour =
1 minute =
60 minutes
60 seconds

5. Convert 1 hour to seconds
1 hour = 60 minutes
1 minute = 60 seconds
So 1 hour =60minutes x 60seconds
1 hour =3600 seconds

6. Determine mph (speed) 1miles • 3600sec = 65 sec hour 55.3 miles hour

7. Using Rates Miles per gallon = mpg
If it takes 11 gallons to drive 250 miles, What is the mpg?
250 miles / 11 gallons =
22.7 miles / gallon
22.7 mpg

8. Using Rates Dollar / hour = hour wage
If you work 4 hours and get paid $20.00, What is your hourly wage?
20 dollars / 4 hour =
5 dollars / hour

9. Using Ratios
Hair grows at a rate of 5 inches per year. How much would your hair grow in 6 months?
5inches • 1 year = 1 year
2.5 inches
5 inches 2

10. Classwork
Do worksheet 2.8
homework
page 110 (1-19)