A car has a tire with a diameter of 0.6 meters and turns 400 times per minute. How many kilometers per hour does the car travel?
一辆汽车的轮胎直径是0.6米，每分钟转400圈，这辆汽车每小时行多少千米？
<gadget id="calculator">1 * 1_000</gadget>
<output>1_000</output>

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

<gadget id="calculator">3.14 * 0.6 * 400 * 1 * (3/50)</gadget>
<output>45.216</output>

<result>45.216</result>