The diameter of a bicycle wheel is 0.5 meters. If the wheel rotates 200 times per minute, how many meters does it travel per minute?
一辆自行车的车轮直径是0.5米，如果车轮每分钟转200周，它每分钟前行多少米．
<gadget id="calculator">3.14 * 0.5 * 200</gadget>
<output>314</output>

<result>314</result>