If $\theta$ is an acute angle of a right triangle where $\sin \theta = x/2$, compute the value of $\sin 2\theta$ in terms of $x$.

$\begin{align} \sin 2\theta & = 2\sin \theta \cos \theta \\ \\ & = 2 \cdot \dfrac{x}{2} \cdot \dfrac{\sqrt{4 - x^2}}{2} \\ \\ & = \frac{1}{2}x\sqrt{4 - x^2} \end{align}$