Cut a 5m long cylindrical wood into 3 small cylinders, the surface area increases by 3.14m**2, what is the original volume of this wood in m**3.
把一个5m长的圆柱形状的木料截成3段小的圆柱，表面积增加了3.14m**2，原来这根木料的体积是多少m**3．
<gadget id="calculator">3.14 / 4</gadget>
<output>0.785</output>

<gadget id="calculator">0.785 * 5</gadget>
<output>3.925</output>

<result>3.925</result>