6. (10 points) As shown in the figure, $E$, $F$, $G$, and $H$ are the midpoints of the sides of square $ABCD$. If the area of square $ABCD$ is 144 square centimeters, the area of the shaded part is $\qquad$ square centimeters.
【Solution】Solution: As shown in the figure, the total area of the shaded parts is exactly equal to the total area of the blank parts, so the area of the shaded parts is half of the area of square $A B C D$,

Since the area of square $A B C D$ is 144 square centimeters,

Therefore, the area of the shaded parts is 72 square centimeters.
The answer is 72.