
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
A large triangular poster, shaped like triangle ABC, has a base of 15 cm. The poster is folded from the top, creating a crease DE parallel to the base AB. The area of the resulting upper triangular section, now visible below the base, constitutes 25% of the total area of triangle ABC. Find the length of the crease DE, in cm.

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