
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 large triangle shown has sides of length 5 units. What percentage of the area of the triangle is shaded?
A $80 \%$
B $85 \%$
C $88 \%$
D $90 \%$
E impossible to determine

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