The radius of a circular flower bed is 12 meters. How many meters does it take to walk around the flower bed?
一个圆形花坛的半径是12米，沿着这个花坛走一圈，要走多少米．
<gadget id="calculator">3.14 * 12 * 2</gadget>
<output>75.36</output>

<result>75.36</result>