
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
In square \(R S T U\), a quarter-circle arc with center \(S\) is drawn from \(T\) to \(R\). A point \(P\) on this arc is 1 unit from \(TU\) and 8 units from \(RU\). What is the length of the side of square \(RSTU\)? 

A) 9  
B) 10  
C) 11  
D) 12  
E) 13

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