Cut a cylinder and assemble it into an approximate cuboid, the surface area increases by 8 square centimeters, the height of the cuboid is known to be 4 centimeters, what is the volume of the cylinder in cubic centimeters?
将一个圆柱切开后拼成一个近似的长方体，表面积增加了8平方厘米，已知长方体的高为4厘米，圆柱体的体积是多少立方厘米？
<gadget id="calculator">8 / 2 / 4</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1 * 4</gadget>
<output>12.56</output>

<result>12.56</result>