Cut a piece of square paper with a side length of 8 decimeters into the largest circle, what is the perimeter of the circle.
把一块边长是8分米的正方形纸剪成一个最大的圆形，这个圆形纸板的周长是多少．
<gadget id="calculator">3.14 * 8</gadget>
<output>25.12</output>

<result>25.12</result>