A big clock in the classroom has a minute hand that is 30 cm long. What is the distance traveled by the tip of the minute hand in one revolution?
教室里的一只大钟，它的分针长30厘米，这根分针的尖端转动一周所走的路程是多少厘米．
<gadget id="calculator">3.14 * 2 * 30</gadget>
<output>188.4</output>

<result>188.4</result>