1. C ONVERSION F ACTORS Objective: Learn to use one or more conversion factors to solve rate problems.

2. C ONVERSION F ACTOR What is a conversion factor? A conversion factor is a fraction whose numerator and denominator represent the same quaintly but use different units. Thus the fraction is equal to 1.

3. E XAMPLE : RIGHT? And so on…

4. H ELPFUL H INTS : The conversion factor: Must introduce the desired unit Must cancel the original unit so that the desired unit is all that remains The original unit must be on the opposite side of the conversion fraction.

5. C ONVERTING B ETWEEN M ETRIC AND C USTOMARY U NITS 1 inch is 2.54 cm. A bookmark has a length of 18 cm. What is the length of the bookmark in inch rounded to the nearest inch? Write the proportion Find the cross product Solve for x Round to nearest inch The bookmark is about 7 inches long.

6. F INDING C ONVERSION F ACTORS A. feet to yards There are 3 feet in 1 yard. To convert feet to yards, multiply the number of feet by B. pounds to ounces There are 16 ounces in 1 pound. To convert pounds to ounces, multiply the number of pounds by Find the appropriate factor for each conversion. Remember we need the units in the denominator to cancel.

7. T RY T HIS ! Find the appropriate factor for each conversion. A. Kilometers to centimeters B. Inches to yards C. Hours to weeks Multiply the number of km by this Multiply the number of in by this Multiply the number of hrs by this

8. E XAMPLE 1: The average American uses 580 pounds of paper per year. Find the number of pounds of paper the average American uses per month, to the nearest tenth.

9. E XAMPLE 2: Use a unit conversion factor to convert the units? A. If orange juice sells for $1.28 per gallon, what is the cost per ounce? B. Convert 80 miles per hour to miles per minutes.

10. E XAMPLE 3: A strobe lamp can be used to measure the speed of an object. The lamp flashes every of a second. A camera records the object moving 52 cm between flashes. How fast is the object moving in m/s?