
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
Rectangles $R_1$ and $R_2$, and squares $S_1, S_2,$ and $S_3$ are combined to form a rectangle that is 4000 units wide and 2450 units high. Each of the squares $S_1$ and $S_3$ has its side length equal to the sum of the side length of $S_2$ and the shorter side length of the rectangles $R_1$ and $R_2$. Determine the side length of $S_2$.
A) 770
B) 775
C) 780
D) 785

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