【Question 16】  
As shown in the figure, $A$ and $B$ are the centers of two quarter circles, with radii of 14 cm and 28 cm, respectively. Try to find the difference in area between the two regions labeled I and II. (Take $\pi=\frac{22}{7}$)
【Analysis and Solution】
Geometry, Area, Circle and Sector.
$$
\begin{array}{l}
S_{1}-S_{\mathrm{II}}=\left(S_{\mathrm{I}}+S_{\mathrm{III}}+S_{\mathrm{IV}}\right)-\left(S_{\mathrm{II}}+S_{\mathrm{III}}+S_{\mathrm{IV}}\right)=S_{\frac{1}{4} \text { of the large circle }}-\left(S_{\frac{1}{4} \text { of the small circle }}+S_{\text {rectangle }}\right) \\
=\frac{1}{4} \times \pi \times 28^{2}-\left(\frac{1}{4} \times \pi \times 14^{2}+14 \times 28\right)=147 \pi-392=147 \times \frac{22}{7}-392=70 \text { square centimeters. }
\end{array}
$$