After cutting a cylinder with a height of 4dm into two small cylinders, the surface area increases by 18cm**2, what is the original volume of the cylinder?
把一个高是4dm的圆柱截成两个小圆柱后，表面积增加了18cm**2，圆柱原来的体积是多少．
<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 * 4 * 10</gadget>
<output>360</output>

<result>360</result>