Geometry Angles

[kamalakarthi]

Hi All,

Can you please help me on the attached problem. Thanks in advance.

Thanks,
Karthik.

[[email protected]]

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.

GMAT assassins aren't born, they're made,
Rich

[GMATGuruNY]

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:


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:


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.

[Matt@VeritasPrep]

Here's a quick method in three pictures: