The minute hand of a clock is 20 cm long, what is the distance traveled by the tip of the minute hand after half an hour?
一个时钟的分针长20厘米，经过半小时后分针针尖所走的距离是多少厘米．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 20 * 1</gadget>
<output>62.8</output>

<result>62.8</result>