After sawing a 9-meter-long log into two pieces, the surface area increases by 6.28 square meters. What is the original volume of the log?
把一根9米长的圆木锯成两段后，表面积增加了6.28平方米，原来这根原木的体积是多少．
<gadget id="calculator">6.28 / 2</gadget>
<output>3.14</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>