Cutting a cylinder of wood with a length of 5 decimeters into two cylinders increases the surface area by 12.56 square decimeters. What is the volume of this cylinder in cubic decimeters?
把一根长5分米的圆柱体木料截成两个圆柱体，表面积增加了12.56平方分米．原来这个圆柱体的体积是多少立方分米．
<gadget id="calculator">12.56 / 2</gadget>
<output>6.28</output>

<gadget id="calculator">6.28 * 5</gadget>
<output>31.4</output>

<result>31.4</result>