JEE MAIN - Mathematics (2021 - 24th February Morning Shift - No. 19)
If one of the diameters of the circle x2 + y2 - 2x - 6y + 6 = 0 is a chord of another circle 'C',
whose center is at (2, 1), then its radius is ________.
Answer
3
Explanation
Circle x2 + y2 - 2x - 6y + 6 = 0 has centre
O1(1, 3) and radius r
= 2.
Let centre O2 (2, 1) of required circle and its radius being r.
_24th_February_Morning_Shift_en_19_1.png)
Distance between (1, 3) and (2, 1) is $$\sqrt 5 $$
$$ \therefore $$ $${\left( {\sqrt 5 } \right)^2} + {(2)^2} = {r^2}$$
$$ \Rightarrow r = 3$$
Let centre O2 (2, 1) of required circle and its radius being r.
Distance between (1, 3) and (2, 1) is $$\sqrt 5 $$
$$ \therefore $$ $${\left( {\sqrt 5 } \right)^2} + {(2)^2} = {r^2}$$
$$ \Rightarrow r = 3$$
Comments (0)
