OG16- DS 98

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OG16- DS 98

by amina.shaikh309 » Tue Jun 21, 2016 6:39 am

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by Brent@GMATPrepNow » Tue Jun 21, 2016 7:07 am
There's a good discussion about this question here: https://www.beatthegmat.com/og-79-t111789.html

Cheers,
Brent
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by OptimusPrep » Wed Jun 22, 2016 9:03 pm
amina.shaikh309 wrote:Image
Area (ABC) = 1/2*AC*BC
Area (DBA) = 1/2*DA*AB

Statement 1:
AC = √2* AD. But we do not know anything about the base
ISUFFICIENT

Statement 2:
We just have the information about ABC
INSUFFICIENT

Combining both statements:
On combining, AC = CB, and AC = √2*AD
AB = AC^2 + BC^2 = 2AD + 2AD = 4AD

We have the values of base and perpendicular of both triangles in terms of AD.
Hence we can calculate and compare the area
SUFFICIENT

Correct Option: C