Please reason step by step, and put your final answer within \boxed{}.
Given a regular nonagon \(N\), with \(O\) as the center of its circumcircle, \(PQ\) and \(QR\) as adjacent sides of \(N\). Let \(A\) be the midpoint of \(PQ\), and \(B\) be the midpoint of the radius perpendicular to \(QR\). Find the angle between \(AO\) and \(AB\).
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