In a wall clock, the minute hand is 10 cm long. What is the distance traveled by the tip of the minute hand after half an hour?
一个挂钟，分针长10cm，经过半小时后，分针的尖端所走的路程是多少cm．
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">2 * 3.14 * 5</gadget>
<output>31.4</output>

<result>31.4</result>