A cylindrical container filled with water has a bottom radius of 5 cm, a height of 30 cm, and a water depth of 12 cm. Now put an iron cylinder with a bottom radius of 3 cm and a length of 20 cm into the container vertically until it reaches the bottom. At this time, the water depth of the container is how many.
一个盛有水的圆柱体容器底面半径为5厘米，高30厘米，水深12厘米，现将一个底面半径为3厘米，长为20厘米的铁圆柱垂直放入容器直到底部，这时容器的水深是多少．
<gadget id="calculator">942 / 50.24</gadget>
<output>18.75</output>

<result>18.75</result>