Date: Mon, 19 Apr 1999 18:06:54 0500
Hi, my name is Deanna.
I am in college prealgebra.
My question has to do with unit conversions with English and metric systems. I need to know how to use conversion factors with powers of 10. Which way do i move my decimal point. ex. .48kl to liters. Thank you.
Hi Deanna
The question you are really asking is: "Do I multiply or divide by 10?", because if we multiply by 10 then the decimal point appears to move one place to the right and if we divide by 10 the decimal point appears to move to the left.
You just need to visualize which of the 2 units is the biggest. For example if a bus holds 10 times as many people as a car and if 30 buses are needed to carry everyone then you know that you need 30x10 cars to hold the same number. Since cars are smaller than buses you need more cars than buses, i.e. if you go from a large unit to a smaller unit you must multiply. But if you know that you need only 30 cars to carry everyone then you need 30/10 buses to hold the same number of people. That is, if you go from a small unit to a larger unit you must divide. So if you go from kilolitres to litres you have decide if a kilolitre is more or less than a litre. Since a kilolitre is 1000 L then it is larger. So if you change to the smaller unit (litre) it will take more of them to do the same job and so you multiply. So 45 kL = 45x1000 L = 45 000 L.
I hope that this helps.
Jack
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