Indian Institute of Foreign Trade 2017 Solved Paper

Choice (B) Since AQ and AS are tangents, hence AQ = AS and △AOQ is congruent to △AOS.

Similarly △BSO is congruent to △BTO
Hence ∠ AOB = 180 – θ – α
In the △PAB, 55 + 180 – 2θ + 180 – 2α = 180
⇒ △AOB = 180 – θ – α = 62.5°.