The director circle of the parabola `(y-2)^(2)=16(x+7)` touches the circle `(x-1)^(2)+(y+1)^(2)=r^(2)` then `r` is equal to

The circle (x-r) ^(2) + (y-r) ^(2) =r ^(2) touches

The director circle of the ellispe x^(2)/9 + y^(2)/5 = 1

The parabola y^(2)=4x and the circle (x-6)^(2)+y^(2)=r^(2) will have no common tangent if r is equal to

The parabola y^2 = 4x and the circle (x-6)^2 + y^2 = r^2 will have no common tangent if r is equal to

A straight line x=y+2 touches the circle 4(x^(2)+y^(2))=r^(2), The value of r is:

If the chord of contact of tangents from a point (x_(1),y_(1)) to the circle x^(2)+y^(2)=a^(2) touches the circle (x-a)^(2)+y^(2)=a^(2), then the locus of (x_(1),y_(1)) is