9. (3 points) As shown in the figure, the square $D E O F$ is inside a quarter circle. If the radius of the circle is 1 cm, then the area of the shaded part is $\qquad$ square centimeters. $(\pi$ is taken as 3.14. $)$
9. (3 points) As shown in the figure, the square $D E O F$ is inside a quarter circle. If the radius of the circle is 1 cm, then the area of the shaded part is $\qquad$ square centimeters. $(\pi$ is taken as 3.14. $)$

【Solution】Solution: As shown in the figure,
The area of the square $=$ diagonal $\times$ diagonal $\times \frac{1}{2}$
$=1 \times 1 \times \frac{1}{2}$
$=\frac{1}{2}$ (square centimeters)
The area of the quarter circle $=\frac{1}{4} \times \pi r^{2}$
$=\frac{1}{4} \times 3.14 \times 1^{2}$
$=0.785$ (square centimeters)
The area of the shaded part $=0.785-\frac{1}{2}=0.285$ (square centimeters)
Therefore, the answer is 0.285.