The radius of the driving wheel of the train is 0.75 meters. If it turns 300 times per minute, how many kilometers per hour will it travel?
火车主动轮的半径是0.75米，如果它每分转300圈，每小时行多少千米？
<gadget id="calculator">0.75 * 2</gadget>
<output>1.5</output>

<gadget id="calculator">60 / 1_000</gadget>
<output>3/50 = around 0.06</output>

<gadget id="calculator">3.14 * 1.5 * 300 * (3/50)</gadget>
<output>84.78</output>

<result>84.78</result>