AO² = AB² + OB² AO² = 5² + 12² = 169 AO = 13cm Let P be the point which divides MN in two equal parts Now, In Triangle BOA and MPA ∠BAO = ∠MAP and ∠OBA = ∠MPA Therefore both the Triangles are similar, Hence AP/AB = MP/OB 8/12 = MP/5 MP = 10/3 Length of the Shortest Tangent = 2 ×10/3 = 20/3 cm