The radius of the wheel of a bicycle is 0.3m, how many meters does the wheel advance when it rolls forward 10 times? (The result keeps π)
一辆自行车的车轮半径是0.3m，车轮往前滚动10周前进了多少m．(结果保留π)
<gadget id="calculator">2 * 0.3 * 10</gadget>
<output>6</output>

<result>6</result>