The diameter of a bicycle is 60 centimeters, if it turns 120 times per minute on average, how many kilometers will it travel in half an hour?
一辆自行车的直径是60厘米，如果平均每分钟转120圈，半小时走多少千米？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">30 / 1_000</gadget>
<output>3/100 = around 0.03</output>

<gadget id="calculator">3.14 * (3/5) * 120 * (3/100)</gadget>
<output>6.7824</output>

<result>6.7824</result>