Since the given circles x2+y2−2x−2y−7=0 and x2+y2+4x+2y+k=0 cut orthogonally, then (−2)(2)+(−2)(1)=k−7 ⇒‌‌−4−2=k−7⇒k=1 So, equation of common chord is 6x+4y+8=0⇒3x+2y+4=0 ∴ Length of the chord, AB=2(AM) x2+y2−2x−2y−7=0