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The center of circle Q is on the yaxis, and the circle passes through
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26 Nov 2014, 11:48
Question Stats:
67% (01:21) correct 33% (01:40) wrong based on 209 sessions
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The center of circle Q is on the yaxis, and the circle passes through points (0, 7) and (0, –1). Circle Q intersects the positive xaxis at (p, 0). What is the value of p?
(A) \(\frac{7}{3}\)
(B) \(4\)
(C) \(5\)
(D) \(\sqrt{7}\)
(E) \(\sqrt{11}\)For a set of Coordinate Geometry practice questions with solutions, visit this page: https://magoosh.com/gmat/2013/gmatquan ... questions/Mike
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Re: The center of circle Q is on the yaxis, and the circle passes through
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10 Jun 2015, 18:30
The center of circle Q is on the yaxis, and the circle passes through points (0, 7) and (0, –1). This tells us the circle's center, which is (0,3) and the radius, which is 4.
Circle Q intersects the positive xaxis at (p, 0). we can just use the equation for distance between two points. In this case, (0,3) and (p,0).
4=\(sqrt((03)^2 + (p0)^2)\) p=\(sqrt(7)\)
Answer: (D) \(sqrt(7)\)



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Re: The center of circle Q is on the yaxis, and the circle passes through
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02 Dec 2015, 19:15
agree with D. if center of the circle is on y axis, then it must be the case that r=4 while the center is at 0,3. Now, we can draw a line from 0,3 to the point of intersection of the circle with x axis. the line will have a length of 4, since it is the radius of the circle. we know 2 sides of a right triangle...we can find the 3rd side: 4^2 = 3^2 +x^2, where x is the length of the leg. 16=9+x^2 > x=sqrt 7. since the ycoordinate of the line is 0, then the x coordinate of the intersection of the circle must be sqrt 7.



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Re: The center of circle Q is on the yaxis, and the circle passes through
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28 Mar 2018, 04:55
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