If a square paper with a circumference of 12 decimeters is used to cut out the largest circle, what is the circumference of the circle in decimeters?
如果用一张周长是12分米的正方形纸剪成一个最大的圆形，那么圆的周长是多少分米．
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">3.14 * 3</gadget>
<output>9.42</output>

<result>9.42</result>