答案：$220^\circ$
留意 $\angle PRQ=90^\circ$，則可得
留意 $\angle PRQ=90^\circ$，則可得
$\begin{array}{rcl}
\cos \angle QPR & = & \dfrac{9}{14} \\
\angle QPR & = & 49.994~799~12^\circ
\end{array}$
所以，由 $P$ 測 $Q$ 的方位角
$\begin{array}{cl}
= & 270^\circ – \angle QPR \\
= & 270^\circ – 49.994~799~12^\circ \\
= & 220^\circ
\end{array}$
