On a circular clock face, the length of the minute hand is 12 cm. After 30 minutes, how many centimeters does the tip of the minute hand travel?
一个圆形钟面，分针长12厘米，经过30分钟，分针的尖端走过多少厘米？
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 12 * 1</gadget>
<output>37.68</output>

<result>37.68</result>