
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
 $ABC$  is a triangle. Reflect each vertex in the opposite side to get the triangle  $A'B'C'$ . Find a necessary and sufficient condition on  $ABC$  for  $A'B'C'$  to be equilateral.

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