Unit Conversions - Metric SystemDate: 7/29/96 at 15:51:44 From: Anonymous Subject: Conversions to and from Metric Units Perform the following conversions by multiplying or dividing by the appropriate power of 10. 1. 3.25 cm to millimeters 2. 9.24 km to meters Perform the following conversions. Use a calculator. 3. 1,000 mi to kilometers 4. 7.68 kg to pounds Date: 7/29/96 at 20:8:32 From: Doctor Jerry Subject: Re: Conversions to and from Metric Units My favorite way of doing conversions is to use "unit cancellation." I'll illustrate this by working out questions 1 and 3. If you find this method interesting and useful, perhaps you can work out questions 2 and 4. Think of a fact like 1 mile is the same as 5,280 feet as a ratio; either (1 mile)/(5280 feet) or (5280 feet)/(1 mile). Each ratio acts like the number 1 since the two things are equivalent measures. We use the ratio that allows us to convert units as we wish. Here's question 3. 1000 miles 5280 feet 12 inches 2.54 cm 1 meter 1 km ---------- x --------- x --------- x ------- x ------- x ----------- 1 1 mile 1 foot 1 inch 100 cm 1000 meters Notice that the two miles units cancel, the two feet cancel, the inches cancel, the cm cancels, and the meters cancel. The remaining unit is km, which is what we want. All that remains is to calculate 1000*5280*12*2.54/100/1000 = 1609.344 km. Now, note that I did this in a long way - I wanted to demonstrate just how to use this "unit cancellation" method. If you knew ahead of time that for every mile we have 1.6 kilometers, you could have done the problem in one step instead of five. Can you see how that would go? For the first question, 3.25 cm 10 mm ------- x ----- = 32.5 mm. 1 1 cm Good luck on the other questions. -Doctor Jerry, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
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