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The two regions marked with the letter Y...

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by BTGmoderatorLU » Sun Nov 19, 2017 2:07 pm
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The two regions marked with the letter Y comprise what fraction of the circle above with the center O?

A) 1.
B) 1/2.
C) 1/3.
D) 1/6.
E) 1/12.

The OA is C.

I'm really confused with this PS question. Please, can any expert assist me with it? Thanks in advanced.
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Source: — Problem Solving |

by [email protected] » Mon Nov 20, 2017 2:51 pm
Hi LUANDATO,

This Geometry question is based on a couple of standard line and circle 'rules' that you'll need to know for Test Day:

1) A circle has 360 degrees
2) Each line has 180 degrees
3) Opposite angles in a pair of 'criss-crossing' lines are equal

Based on the drawing, we can see that two lines cross through the center of a circle forming a 120 degree angle. By extension, the angle 'across' from that angle is also 120 degrees and the other two angles are both 60 degrees. Thus, Y=60

Each of the two "Y regions" represents 60/360 = 1/6 of the circle, so the sum of those 2 regions = 1/6 + 1/6 = 2/6 = 1/3 of the circle.

Final Answer: C

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
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by Scott@TargetTestPrep » Thu Oct 17, 2019 7:21 pm
BTGmoderatorLU wrote:Image

The two regions marked with the letter Y comprise what fraction of the circle above with the center O?

A) 1.
B) 1/2.
C) 1/3.
D) 1/6.
E) 1/12.

The OA is C.

I'm really confused with this PS question. Please, can any expert assist me with it? Thanks in advanced.
Since the angles of the two Y regions sum to 120, those regions are 120/360 or 1/3 of the circle.

Answer: C

Scott Woodbury-Stewart
Founder and CEO
[email protected]

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