The length of the hour hand of a clock is 3 cm. How many cm does the tip of the hour hand move in a day and night?
一个时钟的时针长为3cm，这根时针的针尖一昼夜走了多少cm．
<gadget id="calculator">3.14 * 3 * 2 * 2</gadget>
<output>37.68</output>

<result>37.68</result>