The minute hand of an alarm clock is 4 cm long. If it travels for 1 hour, what is the distance traveled by the tip of the needle in cm?
一个闹钟的分针长4厘米，它走了1小时，针尖所行的路程是多少厘米．
<gadget id="calculator">3.14 * 4 * 2</gadget>
<output>25.12</output>

<result>25.12</result>