The solar energy in Li Ming's house is placed on the roof of the sixth floor. Every time he takes a bath, he must first drain the cold water inside. It is known that the length of the conduit is 20 meters and the inner diameter is 2 centimeters. Please do the math, how many liters of water will be wasted if the family of three takes a bath every day?
李明家的太阳能放在六楼的楼顶上，每次洗澡时，他都要先放掉里面的冷水．已知导管的长度是20米，内直径是2厘米，请你算一算，他们一家三口，每天洗一次澡，要浪费多少升水？
<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) * 20 * 10 * 3</gadget>
<output>18.84</output>

<result>18.84</result>