The minute hand of a wall clock is 20cm long, what is the area swept by the minute hand in cm**2.
一座挂钟的分针长20cm，走过1时分针扫过的面积是多少cm**2．
<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

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

<result>1_256</result>