crazy coordinates

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crazy coordinates

by maihuna » Sun Jan 18, 2009 10:04 am
In the rectangular coordinate system, are the points (a, b) and (c, d) equidistant from the origin?

(1) a/b = c/d

(2) (a^2)^1/2 + (b^2)^1/2 = (c^2)^1/2 + (d^2)^1/2
Source: — Data Sufficiency |

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by DanaJ » Sun Jan 18, 2009 10:29 am
Could you please check if you've written statement 2 correctly? I would expect smth like [a^2+b^2]^1/2 = [c^2+d^2]^1/2

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by hypik21 » Sun Jan 18, 2009 10:27 pm
IMO b, if the equation is stated correctly, it infers that A,B,C,D can be negative but they will have the same absolute values. It cant be A because if a was 1 and b was 2, C could be 4, D could be 8, insufficient

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Re: crazy coordinates

by logitech » Mon Jan 19, 2009 12:27 am

In other words IS a^2+b^2=c^2+d^2 ?


(1) a/b = c/d

1/2 = 2/4

Insuf

(2) (a^2)^1/2 + (b^2)^1/2 = (c^2)^1/2 + (d^2)^1/2

Absolute a + b = Absolute c + d

1+4 = 2+3

INSUF

together

We know they are proportional and theirs ABS are the same

So A/B=C/D=1

SUF

I would go with C
LGTCH
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by maihuna » Mon Jan 19, 2009 9:23 am
You rock sir. Its C.

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by maihuna » Mon Jan 19, 2009 9:24 am
DanaJ wrote:Could you please check if you've written statement 2 correctly? I would expect smth like [a^2+b^2]^1/2 = [c^2+d^2]^1/2
See Logitech boss has answered it.