# Can anyone please explain how to convert english units to metric units using dimensional analysis?I'm having problems converting between the two systems.  I know I'm making it harder than it...

Can anyone please explain how to convert english units to metric units using dimensional analysis?

I'm having problems converting between the two systems.  I know I'm making it harder than it really is.  I just need the explanation in relatively simple terms.

ncchemist | eNotes Employee

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Dimensional analysis is the mathematical way to convert a number from one set of units to another set of units.  It can be used to work within metric units, english units, or from one set to another.  The most important thing is to know (or have handy access to) a large number of conversion factors (see the link below).  You then set up a series of fractions to multiply, making sure that the units in the numerators and denominators cancel each other out until you reach the desired unit.  For example of you want to convert 5 inches into centimeters, you need to know that 1 inch is equal to 2.54 centimeters.  Then can can set up the conversion:

5 in * (2.54 cm/1 in) = 12.7 cm

The inch units cancel each other out and you are left with cm.

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