The length of a certain bicycle tire rolling one circle is 157 cm. What is the area of the circle surrounded by this bicycle tire?
某种自行车轮胎滚动一周的长度是157厘米，这种自行车轮胎围成的圆的面积是多少平方厘米？
<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">157 / 6.28</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>