The length of the common chord of the circles x2+y2+4x+1=0 and x2+y2+4y−1=0, is

Given circles intersect orthogonally. So, the length of their common chord is           l=2r1r2r12+r22,where r1 and r2 are the radii of the given circles.Here, r1=5 and r2=3.∴ l=2155+3=152