coordinate geo

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coordinate geo

by beater » Thu Oct 09, 2008 7:48 am
In the xy-plane, the point (-2, -3) is the center of a circle. The point (-2, 1) lies inside the circle and the point (4, -3) lies outside the circle. If the radius r of the circle is an integer, then r =

A. 6
B. 5
C. 4
D. 3
E. 2

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Re: coordinate geo

by Sunny22uk » Thu Oct 09, 2008 8:14 am
beater wrote:In the xy-plane, the point (-2, -3) is the center of a circle. The point (-2, 1) lies inside the circle and the point (4, -3) lies outside the circle. If the radius r of the circle is an integer, then r =

A. 6
B. 5
C. 4
D. 3
E. 2
>There are 2 points- one is internal and the other is external
>Therefore the border of the circle should lie between those 2 points.
>Distance between centre of circle and the internal point= 4(from the formual d=Sqrt of [(a2-a1)^2 + (b2-b1)^2]
>Distance between centre of circle and the external point= 6
>So the radius is between 4 and 6 and since it is an integer
> The answer should be 5
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by rabab » Thu Oct 09, 2008 9:27 am
I don't get it. What does the point outside the circle got to do with the radius? Shouldn't the answer be 2?

Can someone else clarify pls?

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by mental » Thu Oct 09, 2008 9:33 am
this problem was posted on 7th
see the link

https://www.beatthegmat.com/circle-problem-t20276.html

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by beater » Fri Oct 10, 2008 6:32 am
Thanks a lot guys!