Answer
$4.71\text{ cm}^2$
Work Step by Step
Here, $r$ denotes the radius of the sector of the circle.
The Area $A$ of sector can be computed using the fomrula
$A=\frac{\theta}{360}\cdot \pi \cdot r^2$
where $\theta$ is the central angle in degrees.
Use the formula above to obtain
$A=\frac{60}{360}\cdot \pi \cdot 3^2=1.5\pi\approx4.71\text{ cm}^2$