The outer wheel of a car has a diameter of 0.8 meters and rotates at 500 revolutions per minute. What is the speed of the car in kilometers per hour?
一辆汽车外轮直径0.8米，每分钟转500转，这辆汽车的时速是多少千米．
<gadget id="calculator">60 / 1_000</gadget>
<output>3/50 = around 0.06</output>

<gadget id="calculator">3.14 * 0.8 * 500 * (3/50)</gadget>
<output>75.36</output>

<result>75.36</result>