Li Ming measured the circumference of a tree trunk to be 251.2 centimeters. What is the area of the cross-section of the trunk in square centimeters?
李鸣量得一棵树干的周长是251.2厘米．这棵树干横截面的面积是多少平方厘米？
<gadget id="calculator">251.2 / 3.14 / 2</gadget>
<output>40</output>

<gadget id="calculator">40 ** 2</gadget>
<output>1_600</output>

<gadget id="calculator">3.14 * 1_600</gadget>
<output>5_024</output>

<result>5_024</result>