A wire encloses a square whose side length is 4.71 decimeters. If it is rounded, what is the area of the circle in square decimeters?
一根铁丝围成边长是4.71分米的正方形，如果改围圆形，这个圆的面积是多少平方分米．
<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>