
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
The diagonals \( AC \) and \( BD \) of a quadrilateral \( ABCD \) are perpendicular to each other. Given that \( AB = 5 \), \( BC = 4 \), and \( CD = R \), if \( DA = S \), find the value of \( S \).

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