The hour hand of a wall clock is 15 cm long. How many centimeters does the tip of the hour hand travel from 6 am to 9 am?
一只挂钟的时针长15厘米，从早上6时到早上9时，时针的尖端所走过的路程是多少厘米？
<gadget id="calculator">90 / 360</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3.14 * 15 * 2 * (1/4)</gadget>
<output>23.55</output>

<result>23.55</result>