Uncle Wang used a square plank with a circumference of 160 decimeters and sawed it into the largest circle. What is the area of this circle in square meters?
王叔叔用一块周长是160分米的正方形木板，锯成一个最大的圆，这个圆的面积是多少平方米？
<gadget id="calculator">160 / 4 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">400 / 100</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<result>12.56</result>