In the figure above, point P and Q lie on a circle with ...

[ilakshmir]

The GMAT prep q asks for x co-ordinate of point Q given that P(-sqrt(3),1).

If I assume that the center O of the circle is teh origin of the co-ordinate system, then I can compute Q. This seems to be GMAT Preps approach. But it is not explicitly given that O is ta (0,0); so every answer choice could be valid for some location of O!

Isn't this question ambiguous?

[nimish.tiwari]

I think the very fact that the diagram in the Q has x-axis and y-axis passing through O makes it sufficient enough for us to conclude (or assume) that point O infact is that origin of the co-ordinate system.

If x and y axes wouldn't have been mentioned in the diagram anywhere then it'd have been possible to indicate that pt O is not the origin.

Hope this helps!! Atleast that's how I had approached this Q.

[ilakshmir]

Thanks nimish.tiwari!

I guess what you say is reasonable. The OG book illustrates some of the basics of geometry where it does seem to take the intersection of x and y axes as the origin.

[RonPurewal]

Thanks nimish.tiwari!

I guess what you say is reasonable. The OG book illustrates some of the basics of geometry where it does seem to take the intersection of x and y axes as the origin.

yes, the intersection of the x and y axes must be the point (0, 0).

also, make sure you know the following:
* any point on the x axis has the coordinates (something, 0)
* any point on the y axis has the coordinates (0, something)