A cylindrical piece of wood is 4 meters long. After cutting it into two sections, the surface area increases by 25.12 square meters. What is the original volume of this piece of wood in cubic meters?
一根圆柱形的木材，长4米，把它横截成2段后，表面积增加了25.12平方米．这根木材原来的体积是多少立方米．
<gadget id="calculator">25.12 / 2</gadget>
<output>12.56</output>

<gadget id="calculator">12.56 * 4</gadget>
<output>50.24</output>

<result>50.24</result>