A semicircular fish pond with a radius of 12 meters is planned to surround it with a fence. How long is the fence at least?
一个半径12米的半圆形鱼池，计划在它的周围围一圈篱笆，篱笆至少长多少米？
<gadget id="calculator">3.14 * 12</gadget>
<output>37.68</output>

<gadget id="calculator">2 * 12</gadget>
<output>24</output>

<gadget id="calculator">37.68 + 24</gadget>
<output>61.68</output>

<result>61.68</result>