JEE PYQ: Circle Question 10
Question 10 - 2021 (24 Feb Shift 1)
If one of the diameters of the circle $x^2 + y^2 - 2x - 6y + 6 = 0$ is a chord of another circle $C$ whose center is at $(2, 1)$, then its radius is
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Answer: 3
Solution
Circle: $(x-1)^2 + (y-3)^2 = 4$, center $(1,3)$, radius 2. Distance from $(2,1)$ to $(1,3)$ is $\sqrt{5}$. Radius of $C = \sqrt{5 + 4} = 3$.