The area of the circle in the figure on the side measures $20 \mathrm{~cm}^{2}$. If $\widehat{A O B}=60^{\circ}$ and $\widehat{C O D}=30^{\circ}$, what is the area of the region of the circle that is shaded?

![](https://cdn.mathpix.com/cropped/2024_05_01_166d7b619133f9b517e0g-2.jpg?height=372&width=409&top_left_y=2184&top_left_x=1326)
As

$$
60^{\circ}+30^{\circ}=90^{\circ}
$$

it follows that the hatched area represents a quarter of the total area of the circle. Since the area of the circle is $20 \mathrm{~cm}^{2}$, the hatched area is $5 \mathrm{~cm}^{2}$.

![](https://cdn.mathpix.com/cropped/2024_05_01_166d7b619133f9b517e0g-8.jpg?height=372&width=397&top_left_y=425&top_left_x=1338)