The radical axis of circle x2+y2−4x−4y+3=0 and x2+y2+4x−4y+3=0 is −8x=0⇒x=0 The radius axis of circle x2+y2+4x−4y+3=0 and x2+y2+4x+4y+3=0 is −8y=0⇒y=0 ∴ Centre of the required circle =(0,0) Radius = Length of the tangent from (0,0), to each of the given circle. ∴r=√3