A circus monkey performs a tightrope walk on a unicycle. The diameter of the wheel is 20 centimeters. To ride a 31.4-meter steel wire, how many turns does the wheel have to turn.
马戏团小猴表演骑独轮车走钢丝，车轮的直径是20厘米，要骑过31.4米的钢丝，车轮要转动多少圈．
<gadget id="calculator">31.4 * 100</gadget>
<output>3_140</output>

<gadget id="calculator">3.14 * 20</gadget>
<output>62.8</output>

<gadget id="calculator">3_140 / 62.8</gadget>
<output>50</output>

<result>50</result>