Draw the largest circle in a rectangle with a length of 7 decimeters and a width of 4 decimeters. What is the circumference of this circle? (π takes 3.14)
在长7分米，宽4分米的长方形里画一个最大的圆，这个圆的周长是多少．(π取3.14)
<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<result>12.56</result>