Chapter 3: Measurement, Distance

and Scaling

Warm UpDecember 3, 2012

• Look at the two pictures below and write down at least 6 sentences (3 for each picture) that describe what you see.

Unit Rate

• Comparing a certain amount of one item to one of another.– 10 miles per 1 gallon (10:1, 10/1)– 60 miles per 1 hour (60:1, 60/1)– $8.25 per 1 hour ($8.25:1, $8.25/1)– 250 calories per 1 minute (250:1, 250/1)– $2.50 per 1 gallon ($2.50:1, $2.50/1)

Unit Rates (cont.)

• Work with a partner and write a list of at least 5 unit rates.

Finding a Unit Rate

• 5 children went trick or treating for Halloween. At the end of the night, they put all of their candy into one pile and counted that they had 25 pieces total. If each child gets the same number of pieces of candy, how many pieces does one child get?

Eric Josh Cooper Rosy Lori

Finding a Unit Rate (cont.)

1. How many children are there?2. How many pieces of candy are there?

25 ÷ 5 = 5Unit Rate: 5 pieces of candy per 1 child (5:1, 5/1)

Eric Josh Cooper Rosy Lori

Finding a Unit Rate (cont.)

• If Miss Gliot drove 840 miles from Chicago to Charlotte in 12 hours, how fast was she driving?

Finding a Unit Rate

840 miles n miles12 hours 1 hour

(800 x 1) = (12 x n)

800 = 12n

(800/12) = n

n= 70 miles per hour (70:1, 70/1)

Finding a Unit Rate (cont.)

• Timothy worked as a cashier at a grocery store for 10 hours last Saturday. If he made $100 for the day, how much did he make per hour?

Finding a Unit Rate (cont.)

10 hours 1 hours$100 $ n

10 (n) = 100 (1)

10n=100

n= 100/10n=10

Unit Rate Partner Work

1. SuperFoods has oranges on sale at 10 for $2.a. What is the cost per orange?b. How many oranges can you buy for $1?

2. Natalie used 22 gallons of gas to go 682 miles.a. How much gas did she use per mile?b. How many miles did she go per gallon?

3. A 5-minute shower requires 18 gallons of water.a. How much water per minute does a shower take?

b. How long does a shower last if you use only 1 gallon of water?

Exit TicketDecember 3, 2012

Write down 4 examples of unit rates.

1.2.3.4.