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square root

by kylie
(usa)











































I'm not understanding this -(sqrt)81/144

do i just divide 81 into 144 and i get 9/16 is that right

Comments for square root

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Nov 11, 2010
Square Root - Fractions
by: Staff


The question:

by Kylie
(USA)

Im not understanding this -(sqrt)81/144

do i just divide 81 into 144 and i get 9/16 is that right


The answer:


The square root of the fraction (81/144)

= the square root of 81 divided by the square root of 144



sqrt(81/144) = sqrt (81)/sqrt (144)

sqrt(81/144) = sqrt (9 * 9)/sqrt (12 * 12)

sqrt(81/144) = 9/12


This fraction should be reduced to its simplest form:

9/12 = (3 *3)/(4 * 3)

One of the 3’s in the numerator cancels with the 3 in the denominator, so that

9/12 = 3/4

The final answer to your question is: + or -3/4, or + or - 0.75
(note that a square root has two answers, + and -)



In general, it’s a good idea to check your final answer with a calculator when you can.

Google’s free on-line calculator is located here:

http://www.google.com/intl/en/help/features.html#calculator


Just enter: sqrt(81/144), then press carriage return

The answer will be: 0.75


There are some good examples of finding the square root of various types of fractions here:

http://www.solving-math-problems.com/simplifying-radicals-dividing-radicals.html



Thanks for writing.


Staff
www.solving-math-problems.com


Jul 06, 2011
square roots that start off negative
by: Anonymous

what if a sqrt starts out as a negative as in -sqrt 81/144 does it only have one answer then since a negative times itself is a positive and a positive and negative is a negative if it starts out negative does it only have the one solution?

Jul 07, 2011
square root
by: Staff


The answer:


-sqrt(81/144)

= (-1)* [±(3/4)]

1st answer:

= (-1)* [+(3/4)] = -(3/4)

2nd answer:

= (-1)* [-(3/4)] = +(3/4)


There are still two solutions: -(3/4) and +(3/4)

Thanks for writing.


Staff
www.solving-math-problems.com


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