A fence is built around a circular flower bed with a radius of 15 meters. How long is the fence?
在一块半径15米的圆形花坛周围围一圈篱笆，篱笆长多少米？
<gadget id="calculator">3.14 * 15 * 2</gadget>
<output>94.2</output>

<result>94.2</result>