A cylinder with a height of 20 cm, if its height increases by 2 cm, then its surface area increases by 125.6 cm2. Find the volume of the original cylinder.
一个高为20厘米的圆柱体，如果它的高增加2厘米，那么它的表面积就增加125.6平方厘米．求原来这个圆柱体的体积．
<gadget id="calculator">125.6 / 2</gadget>
<output>62.8</output>

<gadget id="calculator">62.8 / 3.14 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100 * 20</gadget>
<output>6_280</output>

<result>6_280</result>