
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
$ABCD$ is a rectangle whose area is 18 square units. The rectangle is subdivided into smaller squares, each with an area of 1 square unit. A semicircle with diameter $AB$ is drawn inside the rectangle. How many square units are contained in the area of trapezoid $EFBA$ with points $E$ and $F$ on $AB$ such that $E$ and $F$ cut two squares from the rectangle, and what is the area of the region under semicircle portion of EFBA?

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