In a rectangular water basin with a length of 120 cm and a width of 60 cm, put a cuboid iron block, so that the water level will rise by 3 cm compared to the original one. It is known that the length and width of the iron block are both 20 cm. Find the value of the iron block high.
在一只长120厘米，宽60厘米的长方形水盆里，放入一块长方体的铁块，这样水面就比原来上升3厘米，已知铁块的长和宽都是20厘米，求铁块的高．
<gadget id="calculator">120 * 60 * 3</gadget>
<output>21_600</output>

<gadget id="calculator">20 * 20</gadget>
<output>400</output>

<gadget id="calculator">21_600 / 400</gadget>
<output>54</output>

<result>54</result>