The angle between two tangents drawn from an external point to a circle is 60°. What is the angle subtended by the chord connecting their points of contact at the center?
120°
Let \(P\) be the external point and let the two tangents touch the circle at \(A\) and \(B\). Then \(\angle APB = 60^\circ\).
The radii \(OA\) and \(OB\) are perpendicular to the tangents at the points of contact:
\(\angle OAP = \angle OBP = 90^\circ\)
In the quadrilateral \(OAPB\), the four angles must sum to 360°:
\(\angle AOB + \angle APB + \angle OAP + \angle OBP = 360^\circ\)
\(\angle AOB + 60^\circ + 90^\circ + 90^\circ = 360^\circ\)
\(\angle AOB = 360^\circ - 240^\circ = 120^\circ\)
The chord \(AB\) subtends \(\angle AOB = 120^\circ\) at the centre — option (2).
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