# Dimensional Analysis Math

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Anyone out there that can give me the correct formula for the dimensional analysis math I am trying to refresh my brain as we start next week and have a math test on that thursday so please anyone?

Thanks

Specializes in med/surg, telemetry, IV therapy, mgmt. Has 40 years experience. 4 Articles; 14,603 Posts

there are weblinks to tutorials on dimensional analysis math on post #3 of this sticky thread:

1,112 Posts

Anyone out there that can give me the correct formula for the dimensional analysis math I am trying to refresh my brain as we start next week and have a math test on that thursday so please anyone?

Thanks

My favorite kind of math. To me it just makes so much sense.

I'll try and explain it as I understand it.

you have a problem and that problem has an equivalent for example.

1kg is equal to 2.2lbs 1kg=2.2lbs

14kg is how many lbs?

the thing you need to know how to do is set the problem up so the "like" formats cancel each other out.

14kg X 2.2lbs/1kg= 30.8lbs

In this case because we are going kg to lbs we multiply 2.2lbs over 1 kg. The units of measure kg cancel each other out and you are left with the correct units lbs.

If you were trying to find how many lbs you would reverese that and divide by 2.2lbs the units lbs would cancel and you are left with kg.

If you know your equvalents then you can do absolutely any problem that way.

2. How many mL in a qt of milk?

if you don't know your equavalent for qt to mL how about oz to mL and make it a two step problem..

1oz=30mL

1Qt=32oz

a) convert qt to ounces 32oz

b)convert ounces to mL

32 ounces times 30mL equal to 10z

32oz X 30mL/10z

again make sure you can cancel your units of oz to end up with units in mL.

hope that helped.

Specializes in med/surg, telemetry, IV therapy, mgmt. Has 40 years experience. 4 Articles; 14,603 Posts

there is no "formula" per se for dimensional analysis. you will use formulas for drug calculations. dimensional analysis' other name is the "factor label method". the reason it is called this is because you set up your problems so that the descriptive labels that go with the numbered terms are arranged so they can be factored out and you are ultimately left with the labels that you want on the final answer. often, it involves ending up with a ratio (fraction) where you have numbers in the numerator and denominator with a "label" attached to each, although not always. these labels are things like "mg", "gram", "ml", "cc", "units", etc. please read the tutorials i referred you to. you can see many problems that i have worked for students by dimensional analysis on this thread: https://allnurses.com/forums/f205/dosage-calculations-88867.html

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