Ok, my math is really rusty but I'm in the midst of

Question

Ok, my math is really rusty but I'm in the midst of preparing for the GMATs and need your help.

How do you simplify radicals? So for instance, you have to simplify radical 576...(the answer is 24). But how would you get to that answer without having to memorize that 24^2 = 576?

GMAT TIGER · Answer

factorization.

576 = 2x2x2x2x2x2x3x3 = (2x2x2x3)^2 = 24^2

eschn3am · Answer

Unfortunately memorizing is the easiest way to go for these. However, you can also break it down step by step:

$formdata=sqrt{576}$

576=2*288
2*2*144
2*2*12*12

and you can keep simplifying or realize that we have

$formdata=sqrt{(12*2)(12*2)}$

12*2 = 24 and there's your answer 8-)

bmwhype2 · Answer

benchmark it. sqrt625 is 25 so the sqrt 576 should be relatively close.

eschn3am · Answer

That certainly works for getting close, but you can't assume 576 is a perfect square right off the bat. Just know that your answer will be somewhere in that vicinity.

bmwhype2 · Answer

true, in my case, i find it helpful because i memorized squares up to 25. sometimes i cant pinpoint a square, say 17^2, but i know 18^2 is 324 so the closest number i memorized below 324 was 289.

junkbondswap · Answer

I like BMWs approach and will probably begin memorizing up to 25

I did the problem quickly by thinking of the first divisor of 576 that also had an easy square root (4)

sqrt 4 * sqrt 144 = 2 * 12 = 24

Ok, my math is really rusty but I'm in the midst of

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