A cylinder is 4 decimeters long, if it is cut into two sections along the cross section, the surface area will increase by 6.28 decimeters2. What is the volume of this cylinder in cubic decimeters?
一个圆柱长4分米，如果沿横截面把它截成两段，表面积增加6.28平方分米．原来这个圆柱的体积是多少立方分米？
<gadget id="calculator">6.28 / 2</gadget>
<output>3.14</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<result>12.56</result>