
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
As shown in the diagram, a rectangular container has an iron column inside it. The base area of the container is $200 \mathrm{~cm}^{2}$, and the base area of the iron column is $40 \mathrm{~cm}^{2}$. The height of the water surface inside the container is $16 \mathrm{~cm}$. When the iron column is lifted up by ___ cm, the distance from the bottom of the iron column to the water surface is $4 \mathrm{~cm}$.

Present the answer in LaTex format: \boxed{Your answer}
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