Circle C: x2+y2+8x−6y+k=0 Length of tangents drawn by an external points to the circle is √S1. Now, the length of tangent drawn by (−2,3) to the circle is L, L=√S1 L=√(−2)2+(3)2+8(−2)−6(3)+k ⇒4=√4+9−16−18+k where L=4 ⇒4=√k−21 ⇒16=k−21 ⇒k=16+21 ⇒k=37