6. Find the unknown angle

A tangent \(AB\) is drawn from a point \(A\) to a circle with centre \(O\). Suppose \(BOC\) is the largest chord of the circle such that \(\angle AOC\) \(=\) \(107^{\circ}\), then find the \(\angle OAB\).

 

Answer:

 

\(\angle OAB\) \(=\) \(^{\circ}\)