The circumference of the base of a cylinder is equal to the height. If the height is shortened by 2cm, its surface area will be reduced by 62.8cm**2. Calculate the volume of the original cylinder.
一个圆柱体的底面周长和高相等，如果高缩短2cm，则其表面积比原来减少62.8cm**2，求原来圆柱的体积．
<gadget id="calculator">62.8 / 2</gadget>
<output>31.4</output>

<gadget id="calculator">31.4 / 2 / 3.14</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<gadget id="calculator">78.5 * 31.4</gadget>
<output>2_464.9</output>

<result>2_464.9</result>