If a cylinder with a base radius of 2 decimeters is divided into several parts and assembled into an approximate cuboid, the surface area increases by 12 square decimeters. What is the volume of this cylinder in cubic decimeters?
把一个底面半径是2分米的圆柱，等分成若干份后拼成一个近似的长方体，表面积增加了12平方分米，这个圆柱的体积是多少立方分米？
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">12 / 2 / 2</gadget>
<output>3</output>

<gadget id="calculator">3.14 * 4 * 3</gadget>
<output>37.68</output>

<result>37.68</result>