A cylindrical wood with a length of 2.5 meters is sawn into three cylinders on average, and the surface area increases by 12.56 square decimeters. What is the volume of this piece of wood in cubic decimeters?
一根长2.5米的圆柱形木料，把它平均锯成三个圆柱体，则表面积增加12.56平方分米．这根木料的体积是多少立方分米．
<gadget id="calculator">12.56 / 4</gadget>
<output>3.14</output>

<gadget id="calculator">3.14 * 2.5 * 10</gadget>
<output>78.5</output>

<result>78.5</result>