cylindrical iron bucket, the radius of the inner bottom of the bucket is 2 decimeters, and the height is 3 decimeters. If the water in the bucket accounts for 80% of the volume, how many liters of water is there in the bucket?
一个圆柱形铁桶，桶内底面半径是2分米，高3分米，如果桶内装水占容积的80%，桶里有水多少升？
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">3.14 * 4 * 3 * (4/5)</gadget>
<output>30.144</output>

<result>30.144</result>