After a 1-meter-long cylindrical wood is cut into two identical half cylinders along the diameter of the bottom surface, the surface area increases by 40 square decimeters. What is the volume of this wood in cubic decimeters?
把一根1米长的圆柱形木料沿底面直径切割成两个完全一样的半圆柱后，表面积增加了40平方分米，这根木料的体积是多少立方分米．
<gadget id="calculator">40 / 2 / 1</gadget>
<output>20</output>

<gadget id="calculator">20 * 10</gadget>
<output>200</output>

<gadget id="calculator">200 / 200</gadget>
<output>1</output>

<gadget id="calculator">1 ** 200</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1 * 1 * 10</gadget>
<output>31.4</output>

<result>31.4</result>