The hour hand of a wall clock is 2.5 centimeters long. How many centimeters does the tip of the hour hand move in a day and night?
一个挂钟的时针长2.5厘米，一昼夜这根时针的尖端走了多少厘米．
<gadget id="calculator">3.14 * 2.5 * 2 * 2</gadget>
<output>31.4</output>

<result>31.4</result>