lf a circle `C` passing through `(4,0)` touches the circle `x^2 + y^2 + 4x-6y-12 = 0` externally at a point `(1, -1),` then the radius of the circle `C` is :-

Explanation

the eqn of line which circle touches is `x^2+y^2+4x-6y-12=0`
So, c= (-2,3)
r= `sqrt (4+9+12)` = 5
no let the intersection point of two circle as A
the centre of the circles be C1, C2 respectively.
so,A is (1,-1)
c1= (-2,3)
let c2= `(alpha, beta)`
...