Reviewing Conversion Factors

Reviewing Conversion Factors

Explore Centimeters and Inches

Opening

Explore Centimeters and Inches

  • Open the interactive and move the slider above the ruler to 1 inch.
    About how many centimeters are equal to 1 inch?

  • Move the slider below the ruler to 1 centimeter.
    About how many inches are equal to 1 centimeter?

INTERACTIVE: Interactive Ruler

Hint:

Use the sliders on the ruler to find rates.

Math Mission

Opening

Find conversion factors and use them to solve problems.

Unit Conversions

Work Time

Unit Conversions

A conversion factor is a rate used to convert from one unit of measure to another unit of measure, where the types of things being measured are the same (for example, length to length or weight to weight). Only the units are different.

  • Find a conversion factor that you can use to convert inches into centimeters.
  • Use your rate to convert 9 inches into centimeters. Check your answer using the ruler.
  • Find a conversion factor that you can use to convert centimeters into inches.
  • Use your rate to convert 25 centimeters into inches. Check your answer using the ruler.

INTERACTIVE: Ruler

Hint:

  • Use the ruler to find the conversion factor of inches per centimeter or centimeters per inch.
  • Would the number of inches be more or less than the number of centimeters for the same length?
  • Once you have the rate, what operation do you need to use to make the conversion?
  • Can you use a double number line or a ratio table to help you make conversions?

Prepare a Presentation

Work Time

Prepare a Presentation

  • Prepare a presentation about the method you used to find the conversion factors to convert from one unit to another.

Challenge Problem

  • Write an explanation of the similarities and differences among unit price, fuel efficiency, population density, speed, and conversion factors. Be prepared to present your explanation to the class.

Make Connections

Performance Task

Ways of Thinking: Make Connections

Did any of your classmates use a method that is different from the one you used to find the conversion factors and solve the problems?

  • Take notes on the different approaches.

Hint:

As your classmates present, ask questions such as:

  • Explain how you used the ruler to find conversion factors.
  • Where do you see the conversion factor in your method? Where do you see the answer?
  • Why is multiplication rather than division the correct operation to use to make the conversions?
  • What happened to the units as you performed the multiplication?

Miles and Kilometers

Work Time

Miles and Kilometers

There are approximately 1.6 kilometers per mile. Use this conversion factor to solve these problems.

  • How many kilometers are in 10 miles?
  • How can you express the speed limit 55 miles per hour in kilometers per hour?
  • The distance between New York City, New York, and Los Angeles, California, is 2,445 miles. What is this distance in kilometers?

Hint:

  • Would the number of kilometers be more or less than the number of miles?
  • If you have the conversion factor, what operation do you need to use to make the conversion?

Conversion Factors as Rates

Formative Assessment

Summary of the Math: Conversion Factors as Rates

Write a summary of what you have learned about conversion factors.

Hint:

Check your summary.

  • Does your summary explain what a conversion factor is and how to use it?
  • Does your summary include the term rate ?
  • Does your summary describe how to convert inches to centimeters and centimeters to inches?

Reflect On Your Work

Work Time

Reflection

Write a reflection about the ideas discussed in class today. Use the sentence starter below if you find it to be helpful.

What I learned about conversion factors from someone else in class is …