After cutting a cylindrical steel rod with a length of 9 decimeters into two parts, the surface area increases by 2.4 square decimeters compared to the original one. What is the original volume of this cylindrical steel rod?
把一根9分米长的圆柱体的钢棍，截成两段后，表面积比原来增加2.4平方分米，这根圆柱形的钢棍原来的体积是多少．
<gadget id="calculator">2.4 / 2</gadget>
<output>1.2</output>

<gadget id="calculator">1.2 * 9</gadget>
<output>10.8</output>

<result>10.8</result>