A cylinder is 1 meter long. After connecting a section of 4 cm, the surface area increases by 251.2 square centimeters. What is the original volume of the cylinder in cubic centimeters?
一个圆柱长1米，接上4厘米的一段后，表面积增加了251.2平方厘米，原来圆柱的体积是多少立方厘米？
<gadget id="calculator">251.2 / 4 / 3.14 / 2</gadget>
<output>10</output>

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

<gadget id="calculator">3.14 * 100 * 1 * 100</gadget>
<output>31_400</output>

<result>31_400</result>