Cut a cuboid with a square cross section into the largest cone. It is known that the circumference of the bottom of the cone is 6.28 cm and the height is 5 cm. What is the volume of the cuboid?
把一个横截面为正方形的长方体，削成一个最大的圆锥体，已知圆锥体的底面周长6.28厘米，高5厘米，长方体的体积是多少？
<gadget id="calculator">6.28 / 3.14</gadget>
<output>2</output>

<gadget id="calculator">2 * 2 * 5</gadget>
<output>20</output>

<result>20</result>