can someone help me pleeeeeeeeease (metric question)

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4.16M=_________dm

ok so this is how I set it up

4.16M x 1m/1000000M x 10dm/1m= 0.0000416

Well what I have isn't one of the answers

a. 416

b.41.6

c. 0.416

d. 4160

So can anyone tell me what I am doing wrong? I feel so dumb.

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4.16M (100cm/1M) = 416cm

416cm(1dm/10cm) = 41.6dm

first I changed to cm, then to dm, answer 41.6 dm

if you did it from mm it would be:

4.16M(1000mm/1M) = 4160mm

4160mm(1cm/10mm) = 416cm

then go to the above conversions, hope it helped;)

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oh...i thought that capital M meant micrometer but its just meter-that makes soo much more sense! thanks!!!

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Specializes in med/surg, telemetry, IV therapy, mgmt.

you are applying your conversion factors incorrectly. m = meters. more commonly, it is just written with a smaller case "m". the conversion factor you want is

1 meter = 10 decimeters,
or
10 decimeters = 1 meter

that very simply makes the problem, by dimensional analysis (factor label method) so that you end up with the label, "dm", in the numerator of the final answer, like this:

4.16 m(eter) x 10 decimeter/1 meter
(you set up this conversion factor as a fraction, which is still a ratio, so that the label "meter" is in the denominator position and it will serve it's purpose to cancel out the "meter" label in the numerator position of the first term of the equation. what you have left to do is carry out the arithmetic and carry through the only remaining label which is what you want in the final answer)
=
41.6 dm

you can double check this answer on http://www.convert-me.com/en/ where you can use this website converter to check your answers to these kinds of problems.

there is also a sticky thread where i have worked a number of medication calculation problems by dimensional analysis. this is nothing more than applying conversion factors in such as way as to manipulate and factor out unwanted labels on the numbers of the problem. it is a technique used in physics and chemistry.

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Thanks! I thought it was stating on the worksheet to convert 4.16 Micrometers to _______dm. On all the other problems it uses a lower case m to depict meters so I got confused.

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Specializes in med/surg, telemetry, IV therapy, mgmt.

Well, it is asking you to convert to dm. It's just that I did it by dimensional analysis which is a method of manipulating the labels on the numbers using a series of ratios (fractions). When you work up to medication calculations where you are given dosages in kilograms and the patient given in pounds, then you need to convert the patient's weight to kilograms or convert the kilograms to the patient's weight in pounds, one way or the other to determine the correct dosage.

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Thanks Daytonite! I have been practicing and using the dimensional analysis that you showed me. I had such a hard time understanding it all until you posted...now I am getting it. I am such a mathaphobic. I start the RN program in August and want to get my footing with this. I don't just want to be able to past the tests but really really understand it because I don't want to make any kinds of dosages mistakes when I am a nurse b/c you can really hurt/kill someone. I am so excited about starting the program and I do have my hands full at home (I am married with two young children ages 3 and 2 months) and a part time caregiver to my sister who is a quad so I am trying to learn as much as I can before I start the program. Thanks so much for your help. I am sure that I will be bothering you some more :)

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Specializes in med/surg, telemetry, IV therapy, mgmt.

well, with that kind of attitude and determination i predict that you're going to shine as a student! as long as i'm on the internet i will answer your questions. i loved math. some of the problems worked out in that dosage calculation thread are real whoppers. most aren't as bad as some of those. here are a couple of really nice websites that you should bookmark on learning how to do dosage calculations. good luck, kiddo!

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Thank you so so much Daytonite! I have been skimming the links and I think that they will really help!

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