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DaveGG
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goldeneagle94
The answer is B.

This is how:

Draw a perpendicular line from the point P onto X-axis. Lets call the point of intersection as A. Now we have a 30-60-90 Right Triangle POA. PA=1. AO= . PO = 2 = QO. (OP = OQ = radius of circle).

This is 1:2: triangle. Angle POA=30 degrees.

Draw a perpendicular line from the point Q onto X-axis. Lets call that point of intersection as B. QBO is a 30-60-90 Right Triangle as well.

Extend the line PO and QO. Using Vertical Angles theorem (Opposite angles), you know Angle QOB = 60.


We know the ratio of a 30-60-90 Right Triangle to be 1:2:.
We know QO = 2. Thus, OB = 1 = s.

s=1.


Although it seems complicated, once you extend the line segments PO and QO and find out all the angles, the problem becomes simple.
Remembering the ratio of the sides of a 30-60-90 Right Triangle and 45-45-90 Right Triangle is very handy for GMAT.

Why is POA in this explanation a 30-60-90 triangle? Could anyone pls explain?
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The ratio of the sides of a 30-60-90 triangle is always 1:2:

You can refer to this link to learn more about the 30-60-90 right triangle - https://www.mathopenref.com/triangle306090.html
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how did you know that this was a 30-60-90 triangle vs 45-45-90?
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Co-ordinates of point P are (-,1).
Now you know that, The Right Triangle PAO has a height of 1 and a base of .

Whenever you see sides in such a ratio in a right triangle, it is a 30-60-90 triangle.
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Co-ordinates of point P are (-,1).
Now you know that, The Right Triangle PAO has a height of 1 and a base of .

Whenever you see sides in such a ratio in a right triangle, it is a 30-60-90 triangle.

Excellent, the light bulb turned on. I'm getting more and more comfortable with 30-60-90 triangle. Thanks. :)
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it all finally clicks! thanks!!



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