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In Fig. 10.11, if $TP$ and $TQ$ are tangents to the circle with centre $O$ and $\angle POQ = 110^\circ$, then $\angle PTQ$ is 
A$60^\circ$
B$70^\circ$
C$80^\circ$
D$90^\circ$
Answer & Solution
Correct answer: B. $70^\circ$
The angle between two tangents from an external point is supplementary to the angle subtended at the centre by the chord joining the points of contact. Therefore $\angle PTQ = 180^\circ - 110^\circ = 70^\circ$. So option B is correct.
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