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by M811 » Thu May 13, 2010 9:24 am
gmatmachoman wrote:"A circle lies in an X-Y plane, with its center at (1, -3). If the distance between the X-intercepts of the circle is 8 units, what is the area of the circle?"

9PI
16PI
25PI
36PI
64PI

Center (1,-3)
X intercepts will be (5,0) and (-3,0)

since (5,0) and (-3,0) are two points on the circle, hence the distance between them will be equal to
radius of the circle

sqrt (4^2 + 3^2) = 5 => radius

Therefore Area - 25PI
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by GauravMalhotra » Thu May 13, 2010 9:58 am
M811 wrote:
gmatmachoman wrote:"A circle lies in an X-Y plane, with its center at (1, -3). If the distance between the X-intercepts of the circle is 8 units, what is the area of the circle?"

9PI
16PI
25PI
36PI
64PI

Center (1,-3)
X intercepts will be (5,0) and (-3,0)

since (5,0) and (-3,0) are two points on the circle, hence the distance between them will be equal to
radius of the circle

sqrt (4^2 + 3^2) = 5 => radius

Therefore Area - 25PI
How did you deduce (5, 0) and (-3, 0) can't it be something else
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by M811 » Thu May 13, 2010 10:33 am
GauravMalhotra wrote:
M811 wrote:
gmatmachoman wrote:"A circle lies in an X-Y plane, with its center at (1, -3). If the distance between the X-intercepts of the circle is 8 units, what is the area of the circle?"

9PI
16PI
25PI
36PI
64PI

Center (1,-3)
X intercepts will be (5,0) and (-3,0)

since (5,0) and (-3,0) are two points on the circle, hence the distance between them will be equal to
radius of the circle

sqrt (4^2 + 3^2) = 5 => radius

Therefore Area - 25PI
How did you deduce (5, 0) and (-3, 0) can't it be something else

It says that the distance between X intercepts is 8 and the considering the center of the circle (1, -3)
you will get only two points (5,0) and(-3,0), by symmetry
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by debmalya_dutta » Thu May 13, 2010 11:52 am
centre is (1,-3). So distance of the centre from X axis = 3
distance between x intercepts = 8 . Hence distance between one of the x intercept points and the foot of the perpendicular from the centre of the circle =4
Hence radius = \/(4^2 + 3^2 = 5

So radius of circle = 25pi
gmatmachoman wrote:"A circle lies in an X-Y plane, with its center at (1, -3). If the distance between the X-intercepts of the circle is 8 units, what is the area of the circle?"

9PI
16PI
25PI
36PI
64PI
Top
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