If a cylinder with a base diameter of 4 decimeters is cut vertically into two identical half cylinders, and the surface area is increased by 16 decimeters, what is the volume of the cylinder in cubic decimeters? (π takes 3.14)
把一个底面直径为4分米的圆柱竖直切开分为相同的两个半圆柱，表面积增加了16平方分米，则圆柱体的体积是多少立方分米．(π取3.14)
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">16 / 2 / 4</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4 * 2</gadget>
<output>25.12</output>

<result>25.12</result>