- Let \(PT\) and \(QT\) be two tangents drawn from the external point \(T\) to the circle with center \(O\).
- Since \(PT\) and \(QT\) are tangents, the angle between a tangent and the radius is always \(90^\circ\), so:
\[ \angle OTP = \angle OTQ = 90^\circ \]
- Also, we know that \(\angle PTQ = \angle OTP + \angle OTQ\), which means:
\[ \angle PTQ = 90^\circ + 90^\circ = 180^\circ \]
- Therefore, \(\angle PTQ = 2 \angle OPQ\).