cylinder is 10 cm high. If its height increases by 2 cm, its surface area will increase by 62.8 cm2. Find the volume of the original cylinder.
一个圆柱高10厘米，如果它的高增加2厘米，那么它的表面积将增加62.8平方厘米，求原来圆柱的体积．
<gadget id="calculator">62.8 / 2 / 3.14 / 2</gadget>
<output>5</output>

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

<gadget id="calculator">3.14 * 25 * 10</gadget>
<output>785</output>

<result>785</result>