An iron wire can just enclose a circle with a radius of 6 cm. If this iron wire encloses an equilateral triangle, what is the side length of this equilateral triangle?
一根铁丝恰好能围成一个半径是6cm的圆，如果把这根铁丝围成一个等边三角形，这个等边三角形的边长是多少．
<gadget id="calculator">2 * 3.14 * 6</gadget>
<output>37.68</output>

<gadget id="calculator">37.68 / 3</gadget>
<output>12.56</output>

<result>12.56</result>