The height of a cylinder is 20cm. After cutting it by 5cm, the surface area of the cylinder is reduced by 31.4cm**2; what is the volume of the original cylinder?
一个圆柱体的高是20cm，将它截去5cm后，圆柱体的表面积就减少了31.4cm**2；原来圆柱体的体积是多少？
<gadget id="calculator">31.4 / 5</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 * 20</gadget>
<output>62.8</output>

<result>62.8</result>