A 31.4m long iron wire is wound into a circle, what is its area in m**2.
一根长31.4m的铁丝绕成一个圆形，它的面积是多少m**2．
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">31.4 / 6.28</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<result>78.5</result>