An iron wire can exactly form a square with a side length of 4.71m. If this iron wire forms a circle, what is the area of the circle in m**2?
一根铁丝恰好可以围成一个边长是4.71m的正方形，如果用这根铁丝围成一个圆，这个圆的面积是多少m**2？
<gadget id="calculator">4.71 * 4</gadget>
<output>18.84</output>

<gadget id="calculator">18.84 / 3.14 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>