Cut the cone from the middle, the height is 18cm, the middle radius is 4cm, and the bottom radius is 8cm. What is the volume of the lower part?
把圆锥从中间切开，高是18cm，中间的半径是4cm，下面的半径是8cm．下面部分的体积是多少？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">(1/3) * 3.14 * 64 * 18</gadget>
<output>1_205.76</output>

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

<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">(1/3) * 3.14 * 16 * 9</gadget>
<output>150.72</output>

<gadget id="calculator">1_205.76 - 150.72</gadget>
<output>1_055.04</output>

<result>1_055.04</result>