
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
In the diagram, $O$ is the center of a circle with radii $OP=OQ=6$. Calculate the perimeter of the shaded region, given that the arc $PQ$ encompasses half of the circle.

[asy]
size(100);
import graph;
label("$P$",(-1,0),W); label("$O$",(0,0),NE); label("$Q$",(1,0),E);

fill(Arc((0,0),1,0,180)--cycle,mediumgray);
draw(Arc((0,0),1,0,180));
fill((0,0)--(-1,0)--(1,0)--cycle,white);
draw((-1,0)--(0,0)--(1,0));
draw((-.1,0)--(-.1,-.1)--(0,-.1));
[/asy]

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