11. (6 points) As shown in the figure, fold a circular piece of paper in half, then fold it in half again, and fold it in half once more, ..., until it is folded for the sixth time. The area of the resulting sector is 5. Therefore, the area of the circular piece of paper is $\qquad$ .
【Analysis】Fold this circular piece of paper once, the angle formed is a straight angle with the center of the circular piece of paper as the vertex and two radii as the sides, straight angle $=180^{\circ}$. Fold it once more, which divides the straight angle into 2 equal parts, each part is $90^{\circ}$. Fold it once more, which divides the $90^{\circ}$ angle into 2 equal parts, each part is $45^{\circ}$. After the sixth fold, it is divided into $(2 \times 2 \times 2 \times 2 \times 2 \times 2)=64$ parts, and the area of the resulting sector is $\frac{1}{64}$ of the area of the circle; solve accordingly.
【Solution】Solution: $5 \div \frac{1}{64}=320$
Answer: The area of the circular piece of paper is 320;
Therefore, the answer is: 320.