A cylindrical container filled with water has a bottom area of 80 cm2 and a depth of 12 cm. Put a cuboid iron rod with a square bottom and a side length of 4 cm vertically into the water. The lower end is in close contact with the container. There is still part of the iron rod exposed out of the water, and the water does not overflow. How deep is the water now in centimeters?
一个装有水的圆柱形容器，其底面积是80平方厘米，其中水深12厘米．将一个底面为正方形边长为4厘米的长方体铁棒竖着放入水中，下端与容器紧密接触，仍有部分铁棒露在水外面，水也没有溢出，现在水深多少厘米？
<gadget id="calculator">80 * 12</gadget>
<output>960</output>

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

<gadget id="calculator">80 - 16</gadget>
<output>64</output>

<gadget id="calculator">960 / 64</gadget>
<output>15</output>

<result>15</result>