Cut a rectangular piece of paper with a length of 5 decimeters and a width of 4 decimeters into the largest circle. What is the circumference of this circle in decimeters?
把一张长为5分米、宽为4分米的长方形纸片剪成一个最大的圆，这个圆的周长是多少分米．
<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<result>12.56</result>