1. Given functions
$$
f(x)=\sin x, g(x)=\sqrt{\pi^{2}-x^{2}}
$$

have the domain $[-\pi, \pi]$. The area of the region enclosed by their graphs is $\qquad$ .
$$
\text { II.1. } \frac{\pi^{3}}{2} \text {. }
$$

If the graph of $y=\sqrt{\pi^{2}-x^{2}}$ is completed to form a full circle, then by central symmetry, it is easy to see that the desired area is half of the area of the circle.