wire can just enclose a square with a side length of 6.28 decimeters. If it is changed to form the largest circle, what is the area of this circle?
一根铁丝刚好可以围成一个边长6.28分米的正方形，如果改围成一个最大的圆，这个圆的面积是多少？
<gadget id="calculator">6.28 * 4</gadget>
<output>25.12</output>

<gadget id="calculator">25.12 / 3.14 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<result>50.24</result>