After increasing the height of a cylinder with a height of 8 decimeters by 3 decimeters, the surface area of the cylinder increases by 18.84 square decimeters. What is the original volume of the cylinder in cubic decimeters?
把一个高为8分米的圆柱的高增加3分米之后，圆柱的表面积比原来增加18.84平方分米，那么原来圆柱的体积是多少立方分米．
<gadget id="calculator">18.84 / 3</gadget>
<output>6.28</output>

<gadget id="calculator">6.28 / 3.14 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1 * 8</gadget>
<output>25.12</output>

<result>25.12</result>