Cut a cylinder into the largest cone, the cut volume is 42 cm**3, what is the volume of this cone in cm**3.
把1个圆柱削成一个最大的圆锥，削去的体积是42厘米**3，这个圆锥的体积是多少厘米**3．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">42 / 2</gadget>
<output>21</output>

<result>21</result>