A cylindrical container with a bottom radius of 12 cm is filled with water. A cylindrical iron rod with a bottom radius of 4 cm is submerged in the water. When the iron rod is taken out, the water level drops by 1 cm. What is the height of the iron rod?
在一个底面半径是12厘米的圆柱形容器里盛满水，水中浸没一个底面半径是4厘米的圆柱形铁棒，当铁棒取出后，水面下降了1厘米，求铁棒的高度？
<gadget id="calculator">12 ** 2</gadget>
<output>144</output>

<gadget id="calculator">3.14 * 144 * 1</gadget>
<output>452.16</output>

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

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

<gadget id="calculator">452.16 / 50.24</gadget>
<output>9</output>

<result>9</result>