If $TP$ and $TQ$ are two tangents to a circle with center $O$ so that $\angle POQ = 110^\circ$, then $\angle PTQ$ is equal to:
$60^\circ$
$70^\circ$
$80^\circ$
$90^\circ$
Step-by-Step Solution
Key Concept: In quadrilateral $OPTQ$, $\angle OPT = \angle OQT = 90^\circ \Rightarrow \angle PTQ + \angle POQ = 180^\circ$.
Stepwise Solution:
$\angle PTQ = 180^\circ - \angle POQ = 180^\circ - 110^\circ = 70^\circ$. [1.0 Mark]
Marking Scheme:
• Calculating $\angle PTQ = 180^\circ - 110^\circ = 70^\circ$: 1.0 Mark
Correct Answer: $70^\circ$