A cylindrical steel is 5 meters long. If it is cut into two sections, the surface area will increase by 12.56 square decimeters. What is the original volume of this steel in cubic decimeters?
一根圆柱形的钢材长5米，如果把它截成两段，表面积比原来增加12.56平方分米，这根钢材原来的体积是多少立方分米．
<gadget id="calculator">12.56 / 2</gadget>
<output>6.28</output>

<gadget id="calculator">5 * 10</gadget>
<output>50</output>

<gadget id="calculator">6.28 * 50</gadget>
<output>314</output>

<result>314</result>