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# Geometry problem

Author Message
Joined: 31 Dec 1969
Location: Russian Federation
GMAT 3: 740 Q40 V50
GMAT 4: 700 Q48 V38
GMAT 5: 710 Q45 V41
GMAT 6: 680 Q47 V36
GMAT 9: 740 Q49 V42
GMAT 11: 500 Q47 V33
GMAT 14: 760 Q49 V44
WE: Supply Chain Management (Energy and Utilities)

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18 May 2008, 15:18
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Can't for the life of me figure this one out.. please explain!
Attachment:

gmatprep 2 geometry problem.JPG [ 52.2 KiB | Viewed 996 times ]
Manager
Joined: 01 May 2008
Posts: 110
Location: São Paulo

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18 May 2008, 15:54
I think it shoulb be C.
Do you have the OE?
Joined: 31 Dec 1969
Location: Russian Federation
GMAT 3: 740 Q40 V50
GMAT 4: 700 Q48 V38
GMAT 5: 710 Q45 V41
GMAT 6: 680 Q47 V36
GMAT 9: 740 Q49 V42
GMAT 11: 500 Q47 V33
GMAT 14: 760 Q49 V44
WE: Supply Chain Management (Energy and Utilities)

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18 May 2008, 16:11
The answer is definitely D - I rechecked to make sure
Senior Manager
Joined: 21 Apr 2008
Posts: 269
Location: Motortown

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18 May 2008, 16:16

Here is the explanation :

Since AB = OC, which is the radius of the circle --> AB = BO, so we have 2 iscoceless traingles, ABO and BOC.
Lets say angles BAO is y, ACO is x.
From option 1: since angle COD is 60, x+y = 180-120= 60
And 2y+180-x = 180for triangle ABO
2y = x
3y = 60
y =20

From option 2 :
x = 40 degrees

From triangle ABO, 2y +180-x = 180
2y = x
so, y = 20

Senior Manager
Joined: 21 Apr 2008
Posts: 269
Location: Motortown

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18 May 2008, 16:28
If you helped me post my first answer to a question, so Thank You
Re: Geometry problem   [#permalink] 18 May 2008, 16:28
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