
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
Two concentric circles are drawn with a smaller circle inside a larger one. The point \( O \) is the common center. A chord \( AB \) of the larger circle, which is 120 units in length, is tangent to the smaller circle. Find the area of the shaded region between the two circles if the radius of the smaller circle is 40 units. Express your answer in terms of \( \pi \).

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