Metric System ConversionsDate: 09/24/98 at 21:14:42 From: Nikki Subject: Metric System Double conversions I need help with the metric system using double conversions. For example: How many centimeters are in 14.25 decameters? How would I solve that using a two-step process? Thanks. Date: 09/25/98 at 08:30:05 From: Doctor Rick Subject: Re: Metric System Double conversions Hi, Nikki. I'll show you a technique I use to be sure I get conversions right. You want to convert dekameters to centimeters. (Or do you mean decimeters? I'll assume dekameters, since maybe you're learning a different spelling.) There is no point in memorizing this conversion factor. All you have to remember is a table of prefixes: ... deka = 10 deci = 1/10 centi = 1/100 milli = 1/1000 ... From this table, you can extract the information you need: 1 dekameter = 10 meters 100 centimeters = 1 meter These can be written as fractions that equal 1: 1 dam 100 cm ----- = ------ = 1 10 m 1 m Now we start with 14.25 decameters, so we multiply by a fraction with dekameters in the denominator, so the dekameters will cancel (just as if they were numbers). That means I must invert the first fraction: 10 m 14.25 dam * ----- = 142.5 m 1 dam Then do the same to convert m to cm. This time I don't need to invert the fraction, because meters are already in the denominator. 100 cm 142.5 m * ------ = 14,250 cm 1 m There's your answer in two steps. What I usually do is to combine the steps into one "chain of ones", like this: 10 m 100 cm 14.25 dam * ----- * ------ = 14,250 cm 1 dam 1 m Just check that the units (dam and m) cancel, so that only cm are left. That shows that you did the conversion correctly. - Doctor Rick, The Math Forum http://mathforum.org/dr.math/ |
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