
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
Isosceles triangles $ABC (AB = BC)$ and $A_{1}B_{1}C_{1} (A_{1}B_{1} = B_{1}C_{1})$ are similar and $AC : A_{1}C_{1} = 5 : \sqrt{3}$. The vertices $A_{1}$ and $B_{1}$ are located on the sides $AC$ and $BC$ respectively, and the vertex $C_{1}$ is on the extension of the side $AB$ beyond point $B$, with $A_{1}B_{1} \perp BC$. Find the angle $B$.

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