The outer radius of a bicycle wheel is 20 cm, how many revolutions does the wheel need to rotate if it needs to travel 125.6 meters?
一辆自行车车轮的外半径为20厘米，如果要行使125.6米，车轮要转动多少圈？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 * 3.14 * (1/5)</gadget>
<output>1.256</output>

<gadget id="calculator">20 / 1.256</gadget>
<output>15.923567</output>

<gadget id="calculator">2 * 3.14 * 15.923567</gadget>
<output>100.000001</output>

<result>100.000001</result>