The radius of the wheel of a truck is 0.5 meters. If the wheel of the truck rotates 300 times per minute, how many kilometers does the truck travel per hour?
一辆货车车轮的半径是0.5米，如果货车的车轮每分钟转300圈，这辆货车每小时行多少千米？
<gadget id="calculator">1 * 60 * 300</gadget>
<output>18_000</output>

<gadget id="calculator">18_000 / 1_000</gadget>
<output>18</output>

<gadget id="calculator">2 * 3.14 * 0.5 * 18</gadget>
<output>56.52</output>

<result>56.52</result>