The circumference of the trunk of a large tree is 157 cm, what is the cross-sectional area of the trunk of this large tree in square centimeters?
一棵大树树干的周长是157厘米，这棵大树树干的横截面积是多少平方厘米？
<gadget id="calculator">157 / 3.14 / 2</gadget>
<output>25</output>

<gadget id="calculator">25 ** 2</gadget>
<output>625</output>

<gadget id="calculator">3.14 * 625</gadget>
<output>1_962.5</output>

<result>1_962.5</result>