A cylindrical container filled with water has a bottom radius of 4 cm, a depth of 20 cm, and a water depth of 16 cm. Put a cylindrical iron rod with a bottom radius of 2 cm and a height of 16 cm vertically into the container. Find the time What is the depth of water in the container?
一个盛有水的圆柱形容器，底面半径为4厘米，深20厘米，水深16厘米，今将一个底面半径为2厘米，高为16厘米的圆柱形铁棒垂直放进容器内，求这时容器的水深是多少厘米？
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

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

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

<gadget id="calculator">16 / 50.24</gadget>
<output>0.318471</output>

<gadget id="calculator">3.14 * 4 * 0.318471</gadget>
<output>3.999996</output>

<gadget id="calculator">3.999996 + 16</gadget>
<output>19.999996</output>

<result>19.999996</result>