cylinder with a base diameter of 2 decimeters is cut off (1/4) and put into a cuboid water tank with a length of 31.4 cm and a width of 20 cm. When fully submerged, the water level rises by 5 cm. Find the volume of the original cylinder.
一个底面直径为2分米的圆柱体，截下它的(1/4)投入到一个长31.4厘米，宽20厘米的长方体水缸中，完全浸没时水位上升5厘米．求原来圆柱体的体积．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">5 / (1/4)</gadget>
<output>20</output>

<gadget id="calculator">31.4 * 20 * 20</gadget>
<output>12_560</output>

<result>12_560</result>