NCERT Exercise 10.2 - Q10 - Circles
Question: Prove that the angle between the two tangents drawn from an external point to a circle is supplementary to the angle subtended by the line-segment joining the points of contact at the centre.
Answer: The angle between the tangents and the angle subtended at the center are supplementary (add up to 180°).
Full step-by-step NCERT solution with diagrams on Something by Zero.