Ans: C
Plot the points $P$, $Q$ and $R$ on the same polar coordinate plane.
Plot the points $P$, $Q$ and $R$ on the same polar coordinate plane.
Note that the required distance is $QX$.
In $\Delta OQX$,
$\begin{array}{rcl}
\theta & = & 340^\circ – 280^\circ \\
\theta & = & 60^\circ
\end{array}$
Hence, we have
$\begin{array}{rcl}
\sin \theta & = & \dfrac{QX}{OQ} \\
QX & = & OQ \times \sin \theta \\
QX & = & 4 \times \sin 60^\circ \\
QX & = & 4 \times \dfrac{\sqrt{3}}{2} \\
QX & = & 2 \sqrt{3}
\end{array}$
