Draw the largest circle in a square whose side length is 4 decimeters. What is the circumference of this circle?
在一个边长是4分米的正方形中画一个最大的圆，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>