Cut off a section of cylindrical steel with a diameter of 20 cm, and cast it into a conical part with a bottom diameter of 10 cm and a height of 30 cm. How long should the steel be cut?
把直径为20厘米的圆柱形钢材截下一段，铸造成底面直径10厘米，高30厘米的圆锥形零件，求要截下多长的钢材？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">30 / 314</gadget>
<output>15/157 = around 0.095541</output>

<gadget id="calculator">(1/3) * 3.14 * 25 * (15/157)</gadget>
<output>2.5</output>

<result>2.5</result>