After sawing an 8-meter-long cylindrical wooden bar into two pieces, the surface area increases by 18 square meters. Find the volume of the original cylindrical wooden bar.
把一根长为8米的圆柱形木条横锯成两段后，表面积增加了18平方米，求原来这根圆柱形木条的体积．
<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 * 8</gadget>
<output>72</output>

<result>72</result>