Xiao Gang measured the circumference of a tree trunk to be 125.6 cm. The cross-section of the trunk of this tree is approximately a circle. What is its approximate area in square centimetres?
小刚量得一棵树干的周长是125.6厘米．这棵树干的横截面近似于圆，它的面积大约是多少平方厘米？
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">125.6 / 6.28</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>