
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
Given $\triangle ABC$ is isosceles with $AB = BC$, a point $D$ is placed on $AC$ such that $AD = DC$, and points $P$ and $Q$ are on $BD$ such that $DP = PQ = QB$, determine the measure of $\angle B$.

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