The line 2 x - y + 1 = 0 is a tangent to the circle at the point 2 ,   5 and the centre of the circle…

The line 2x-y+1=0 is a tangent to the circle at the point 2, 5 and the centre of the circle lies on x-2y=4. Then, the radius of the circle is:
  1. 35
  2. 53
  3. 54
  4. 45

Solution

Given

Slope of OA=5-h-422-h=m1Slope of the given tangent equation=m2=2

5-(h-4)22-h2=-1

h=8

Center=8, 2

Radius=(8-2)2+(2-5)2=35

Asked in: JEE Main 2021 (17 Mar Shift 1)

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