The hour hand of a wall clock is 9 cm long, from the number 12 to the number 12, how many centimeters does the tip of the hour hand travel?
一台挂钟时针长9厘米，从数字12又走到数字12，这根时针的尖端走过多少厘米？
<gadget id="calculator">3.14 * 9 * 2</gadget>
<output>56.52</output>

<result>56.52</result>