# Lesson: Using proportions to convert customary units

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### Lesson Objective

We will be able to convert customary units of measurement.

### Lesson Plan

Do Now: (5 minutes)

1) At a bakery, muffins come in dozens and individual serving containers of orange juice come in packs of 8. If Tiera needs to have the same amount of muffins as orange juice containers, what is the least possible number of sets of each she needs to buy?

2) Write 72 ½ % as a fraction and a decimal.

3) 84 ÷ 0.004

Direct Instruction: (20 minutes)

Give students the following table with one unit missing from each ratio. Have them fill in what they can on their own and then check as a class.

Rates for measurement:
Length                                            Weight                                                         Capacity
1 foot /12 inches                        1 pound /16 ounces                               1 cup /8 fluid ounces
1 yard / 3 feet                             1 ton /2,000 pounds                              1 pint /2 cups
1 mile / 5,280 feet                                                                                        1 quart/ 2 pints
1 gallon/ 4 quarts

Last week we learned that proportions are really just what? How do you think proportions can help us today with converting customary units of measurement?

Ex. Convert 20 feet into inches

Model setting up the proportion.  Be sure to emphasize that the same units must be across from each other.  We can use our conversion chart as one ratio.  When we are converting units of measurement we are showing a proportional relationship.

To convert customary units of measurement:
1) Set up a proportion. Use the unit ratio for one side.
2) Solve for the variable.

Have students add definition for unit ratio to their notes.

Unit ratio- the denominator is 1 unit

Guided Practice: (10 minutes)
Ex. Convert 15 quarts into gallons.

Ex. Convert 4 ½ feet to yards.

Ex. Convert 3 1/2 pounds to ounces.

Ex. Convert 5 yards to inches.

Assessment:(10 minutes)
Converting customary units work-out

### Lesson Resources

 converting customary units work out   Assessment 1,708 Customary Measurement Conversions   Notes 1,837