Our country's water resources are not rich, we must develop the habit of saving water. The inner diameter of a school water pipe is 2 cm. A student forgot to turn off the tap after washing his hands upstairs. It is known that the water in the water pipe flows 50 meters per minute, so how many liters of water will be wasted per minute.
我国的水资源并不丰富，我们要养成节水习惯．学校一种自来水管的内直径为2厘米，一位同学在楼上洗手后忘记关掉水龙头．已知水管内的水每分钟流50米，那么每分钟将浪费多少升水．
<gadget id="calculator">2 / 10 / 2</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) ** 2</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">3.14 * (1/100) * 50 * 10</gadget>
<output>15.7</output>

<result>15.7</result>