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Square root

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Re: Square root

by shahdevine » Tue Aug 11, 2009 3:33 pm
knowledgeisatreasure wrote:Can anyone help me solve this question please:

√576800 is between ?

Answer: 700 and 800

thanks in advance
this is a combo of smart numbers and intuition.

first move: extract sqrt(100) --> sqrt(5768) x sqrt(100)
you have 10 x sqrt(5678)

then i would round 5678 up to 6000 and keep extracting sqrt(100)

so 10 x sqrt(60) x sqrt(100)
so 100 x sqrt(60)

sqrt of 60 is between 7 and 8
so answer is between 100x7 and 100x8=700 and 800

you got this man!
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hmm

by JeffB » Tue Aug 11, 2009 3:44 pm
√576800 is between ?

What square roots are you familiar with? Probably 64 and 49? Just add some zeros for 490000 and 640000

Between 700-800
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by knowledgeisatreasure » Tue Aug 11, 2009 3:44 pm
Thank you,

I didn't think about the rounding to the nearest 1000. I ve done the sqrt of the first 100 though.

thanks a lot.
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by shahdevine » Tue Aug 11, 2009 5:51 pm
knowledgeisatreasure wrote:Thank you,

I didn't think about the rounding to the nearest 1000. I ve done the sqrt of the first 100 though.

thanks a lot.
the reason why i recommend extract as many sqrt(100) as possible before rounding is because if you round at the start to 600000 you might be sloppy and miss a zero somewhere and you will pick wrong answer.
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by knowledgeisatreasure » Wed Aug 12, 2009 12:39 pm
Awesome, thank you so much. You guys make these Questions seem to be a piece of cake.
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by beastly B » Mon Dec 27, 2010 9:45 pm
knowledgeisatreasure wrote:Can anyone help me solve this question please:

√576800 is between ?

Answer: 700 and 800

thanks in advance

700*700=140000 800*800=160000
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