
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
If a tetrahedron has three faces that are right-angled triangles, which of the following types of triangles could possibly be the fourth face of the tetrahedron? (1) Right-angled triangle; (2) Acute-angled triangle; (3) Obtuse-angled triangle; (4) Isosceles triangle; (5) Isosceles right-angled triangle. Fill in the correct serial number(s).

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