The diameter of the train wheel is 0.8 meters. If it rotates 800 times per minute, how many kilometers does the train advance per hour?
火车车轮的直径是0.8米，如果它每分钟转800周，那么这列火车每小时前进多少千米？
<gadget id="calculator">60 / 1_000</gadget>
<output>3/50 = around 0.06</output>

<gadget id="calculator">3.14 * 0.8 * 800 * (3/50)</gadget>
<output>120.576</output>

<result>120.576</result>