Dimensional Analysis Appendix E   Converting to different units of measure.   Convert 12 feet into yards.         12 ft = 4 yds  because          1 yd = 3 ft so          1 yd                            =     1                             3 ft  and multiplying by 1 does not  change the value (property of real numbers).           12 ft                       x  1 yd   =   4 yds                                   3 ft the ft cancel to give answer in yds.   How to determine what is numerator and denominator.  What if we had                      3 ft     12ft  x                    =    ?                    1 yd Does not give us the answer in yards because the ft do not cancel.   Exercise 1:    Change          40miles/hr  into feet/min         1 mi = 5280 ft            1 hr = 60 min Do one step at a time:         40 mi/hr  x  5280 ft/mi  = 40x5280ft/hr         40x5280ft/hr x 1 hr/60min    = 40x5280ft/60min           = 3520 ft/min   How many feet will a car travel in 2 minutes if the car is going 40 mi/hr?           3520 ft/min x 2 min = 7040 ft.   Exercise 2:    Conversions are needed to change US standard system into the Metric system.         1 meter = 39.37 inches         1 kilometer = 1000 meters find          1 kilometer = ? inches = 39370 inches         1 gram = 0.0022046 lbs         1 kilogram = 1000 grams         1 kilogram = ? lbs =  2.2046 lbs Note: ever wonder why lbs represent pounds? ( The Latin word libras means stones used for measuring weight on scales) Back to Finance, Geometry and Logic Main Page Back to the Survey of Math Ideas Home Page