An iron wire can exactly form a square with a side length of 4.71 meters. If this iron wire is used to form a circle, what is the radius of the circle in meters?
一根铁丝恰好可以围成一个边长为4.71米的正方形，如果用这根铁丝改围成一个圆，这个圆的半径是多少米？
<gadget id="calculator">4 / 3.14 / 2</gadget>
<output>0.636943</output>

<gadget id="calculator">4.71 * 0.636943</gadget>
<output>3.000002</output>

<result>3.000002</result>