The radius of the wheel of a truck is 0.5 meters. If the wheels of the truck rotate 280 times per minute, how many kilometers does the truck travel per hour?
一辆货车车轮半径是0.5米，如果货车的车轮每分钟转280圈，这辆货车每小时行多少千米？
<gadget id="calculator">1 * 60 * 280</gadget>
<output>16_800</output>

<gadget id="calculator">16_800 / 1_000</gadget>
<output>84/5 = around 16.8</output>

<gadget id="calculator">2 * 3.14 * 0.5 * (84/5)</gadget>
<output>52.752</output>

<result>52.752</result>