coordinate geo from PREP SOFTWARE

[guest621]

GMAT PREP CAT 2: (Data Sufficiency)

A certain circular area has its center at point P and radius 4, and points X and Y lie on the same plane as the circular area. Does point Y lie outside the circular area?

1. The distance between point P and point X is 4.5.
2. The distance between point X and Y is 9.

Correct answer C.

Can you please help clarify how it is C? I thought it could have been E.

I read it as follows. Point X is outside the circle since it is beyond the distance of the radius with center point P. This is insufficient. B is insufficient because it says nothing in relation to center point P. But I thought the answer could have been E because it doesn't say where X and Y are. It could be anywhere on the plane? I must not be interpreting this properly.

[StaceyKoprince]

First, draw a coordinate plane so you can sketch this out.

You are correct that statements 1 and 2 cannot help us by themselves, so eliminate A, B, and D.

Now, try them together. Pick a point for P - whatever you want - and draw the circle. Place X 4.5 away from P (and, of course, this will be outside of the circle).

Now. Place Point Y 9 spaces away from X, again anywhere you want. Is it possible to put that point inside the circle?

It's not. So the answer to your question is a definitive yes, which is sufficient. And note that although we don't actually know where P, X or Y actually are, the info DOES give us information about where they are relative to each other. That's all we need.

[guest612]

thanks! i think i was trying to make it fit in the circle. now i undertand why it's C!

[StaceyKoprince]

you're welcome!

[rohan]

Hey Stacey,

I'm a little confused here.

I plotted P, the circle and X at 4.5 points to the right of P (which puts it outside the circle). Now because there are no dimensions of the plane mentioned can't Y be placed 9 points to the right of X and hence outside the circle?

Thanks

[messi10]

Hi Rohan,

You are saying the same thing as Stacey. The point is outside the circle, whether you draw it on the left side of X or right side.

Regards

Sunil

[rohan]

yup, sorry I read it wrong.

[RonPurewal]

ok