The hour hand of the big round school clock is 0.8m long. What is the distance traveled by the needle tip in one rotation?
学校圆形大钟的时针长0.8m，它的针尖转动一周走过的距离是多少m．
<gadget id="calculator">2 * 3.14 * 0.8</gadget>
<output>5.024</output>

<result>5.024</result>