In the adjoining figure, TP and TQ are tangents drawn to a circle with centre O. If $\angle OPQ = 15^\circ$ and $\angle PTQ = \theta$, then find the value of $\sin 2\theta$. 
What is the angle between the hour and minute hands at 4:30?
In the given figure, a circle inscribed in \( \triangle ABC \) touches \( AB, BC, \) and \( CA \) at \( X, Z, \) and \( Y \) respectively.
If \( AB = 12 \, \text{cm}, AY = 8 \, \text{cm}, \) and \( CY = 6 \, \text{cm} \), then the length of \( BC \) is: