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InterviewSolution
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The centre of a circle is (a + 2, a -1). Find the value of a if the circle passes through (2,-2)[Ans. a 3]and (8, -2). |
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Answer» Equations of circle =>r^2= (x-a-2)^2 + (y-a+1)^2circle is passing through (2,-2)=r^2 = (2-a-2)^2 + (-2-a+1)^2 = (-a)^2 + (-a-1)^2circle is also passing through (8,-2) = r^2 = (8-a-2)^2 + (-2-a+1)^2 = (6-a)^2 + (-a-1)^2radius is same so (-a)^2 + (-a-1)^2 = (6-a)^2 + (-a-1)^2a^2 = 36 + a^2 - 12a12a = 36a = 3 |
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