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PI "Ï€" on GMAT answers

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PI "Ï€" on GMAT answers

by MAAJ » Tue Jan 25, 2011 4:42 pm
A quick question... I found that in OG Quantitative Review, DS question #95 statement 1 presented the area of a circle without the PI (250 square feet), and the question is to find the radius of the circle. Is this still possible in the actual GMAT format? 'cause if you try to find the radius from the area of the circle which is 250 ft^2 then you need to divide 250 by "PI" and PI, as far as I know, is an irracional number, so we could get a really good estimate but not the exact number. Am I wrong???

r = sqrt(250/PI) is sufficient to answer? yes... :shock: and I though NO because of this.... :(

Also, the question didn't ask for an aproximate... Guess it would be better if they always presented the PI sign next to the number to avoid this confusion..
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by Anurag@Gurome » Tue Jan 25, 2011 9:49 pm
Yes, it is certainly possible for DS questions.
Because for DS questions, they want to test your sense for data sufficiency not your skill of calculation. If a DS questions asks: What is the radius of a circle C? and a statement says The area of circle A is 250 sq. ft., then the answer is The statement is sufficient to answer the problem NOT The radius of the circle is ...

As far as PS problems are concerned, if they generally keep PI outside the calculation or asks you to approximate. In fact while making calculations with PI, always you have to approximate as PI is an irrational number.

For approximation with PI, you can follow any of the strategies:
  • 1. If the answer choices differ from each other so largely that it doesn't matter whether you take PI as 3 or 3.1, you can take PI as 3.
    2. Otherwise you can always take PI as 22/7 and follow the method long division to get a good approximation
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by MAAJ » Wed Jan 26, 2011 7:05 am
Thanks! I'll keep this in mind :)
"There's a difference between interest and commitment. When you're interested in doing something, you do it only when circumstance permit. When you're committed to something, you accept no excuses, only results."
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