A semicircular fish pond has a radius of 10 meters. How many meters does it take to walk around it?
一个半圆形鱼池，半径是10米，如绕其周围走一圈，要走多少米？
<gadget id="calculator">3.14 * 10</gadget>
<output>31.4</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">31.4 + 20</gadget>
<output>51.4</output>

<result>51.4</result>