The outer diameter of a bicycle tire is 71 cm, and the wheel rotates 80 times per minute, how many kilometers does the bicycle travel per hour?
一辆自行车轮胎的外直径是71厘米，车轮每分钟转80周，这辆自行车每小时行驶多少千米．
<gadget id="calculator">60 / 100_000</gadget>
<output>3/5_000 = around 0.0006</output>

<gadget id="calculator">3.14 * 71 * 80 * (3/5_000)</gadget>
<output>10.70112</output>

<result>10.70112</result>