There is a water faucet with an inner diameter of 1 cm, and the speed of water flowing inside is 1 meter per second. When the faucet is opened, how many liters of water can flow out in one minute.
有一个自来水笼头内直径1厘米，里面水流速度是每秒1米，打开笼头，1分钟能流出水多少升．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) ** 2</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">3.14 * (1/4) * 1 * 100 * 1 * (3/50)</gadget>
<output>4.71</output>

<result>4.71</result>