A cylindrical billet with a base radius of 2 cm and a length of 8 cm is forged into a conical part with a base radius of 4 cm. Find the length of this conical part.
把一个底面积半径为2厘米、长为8厘米的圆柱形钢坯锻造成一个底面半径是4厘米的圆锥形零件．求这个圆锥形零件的长．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4 * 8</gadget>
<output>100.48</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<gadget id="calculator">100.48 / (1/3) / 50.24</gadget>
<output>6</output>

<result>6</result>