Tangent Line Angle Calculation

Consider a circle centered at the origin with an external point P, which is located at coordinates (2, 3). A tangent line is drawn from point P to the circle, which has a radius of 3. Let the point of tangency be T. The angle formed between the radius OT (where O is the center of the circle) and the tangent PT can be denoted as $ heta$. Using trigonometric relationships, determine the value of $ an( heta)$. Input your answer as a simplified fraction.