Geometry Angles

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by [email protected] » Sun Sep 21, 2014 10:24 am
Hi Karthik,

This question is perfect for TESTing Values.

I'm going to offer you a couple of hints, so that you can retry this question:

1) Choose a value of X and Y
2) Plug those values into the drawing
3) Fill in the other angles (remember that the angles in a triangle add up to 180 degrees; angles on a line add up to 180 degrees)
4) The above steps should get you a value for W.

5) Plug your values into the 5 answer choices and find the match.

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by GMATGuruNY » Sun Sep 21, 2014 2:44 pm
As Rich has noted, we can PLUG IN angle measurements for x and y and solve for the value of w.
Let x=70 and y=30.
Insert these values into the figure:
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Now insert the rest of the angle measurements, making sure that the angles inside each triangle add up to 180 and that any angles that form a straight line add up to 180:
Image

In the resulting figure, w=20. This is our target.
Now plug x=70 and y=30 into the answers to see which yields our target of 20.
Only A works:
2x + 2y - 180 = 2*70 + 2*30 - 180 = 20.

The correct answer is A.
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by Matt@VeritasPrep » Mon Sep 22, 2014 9:04 am
Here's a quick method in three pictures:


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