∠CAB + ∠DBA = 180° [Angles on the same side of a traversal are supplementary]
1
2
∠CAB +
1
2
∠DBA =
180°
2
∠OAB + ∠OBA = 90° [∵ OA and OB bisect angle ∠CAB and ∠DBA respectively.] In ΔAOB, ∠AOB = 180° ∠OAB - ∠OBA ∠AOB = 90° By using Pythagoras theorem, AB = √OA2+OB2 AB = √62+9.12 AB = √36+82.81 AB = √118.81 AB = 10.9 cm