In a square piece of paper with a circumference of 160 cm, cut out the largest circle, what is the area of this circle in square centimeters?
在一个周长为160cm的正方形纸片内，剪一个最大的圆，这个圆的面积是多少平方厘米？
<gadget id="calculator">160 / 4</gadget>
<output>40</output>

<gadget id="calculator">40 / 2</gadget>
<output>20</output>

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

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<result>1_256</result>