If a cylindrical piece of wood has a base area of 3 square decimeters, if it is cut into 4 sections, the surface area will increase by how many square decimeters.
一根圆柱形的木料，底面积是3平方分米，把它截成4段，表面积增加了多少平方分米．
<gadget id="calculator">3 * 6</gadget>
<output>18</output>

<result>18</result>