If a cylinder with a height of 8 cm is cut along the diameter of the base, the surface area increases by 80 cm2, what is the volume of the original cylinder?
把一个高是8厘米的圆柱沿着底面直径切开，表面积增加了80平方厘米，原来的圆柱的体积是多少？
<gadget id="calculator">80 / 2 / 8 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(5/2) ** 2</gadget>
<output>25/4 = around 6.25</output>

<gadget id="calculator">3.14 * (25/4) * 8</gadget>
<output>157</output>

<result>157</result>