Build a circular path around a circular flower bed. The radius of the flower bed is 2 meters. How long is the path?
在一个圆形花坛的周围修一条环形小路，花坛的半径是2米，这条小路有多长？
<gadget id="calculator">3.14 * 2 * 2</gadget>
<output>12.56</output>

<result>12.56</result>