There is a circular fish pond with a radius of 10 meters, how many meters will it take to walk around it.
有一个圆形鱼池的半径是10米，如果绕其周围走一圈，要走多少米．
<gadget id="calculator">3.14 * 10 * 2</gadget>
<output>62.8</output>

<result>62.8</result>