Recall that the perimeter of a polygon is the sum of the lengths of each side of the polygon.
Since a regular octagon has 8 sides of equal length, and the stop sign is a regular octagon with a side length of 12 in, then its perimeter is:
[tex]\text{Perimeter}=8\times12in\text{.}[/tex]Simplifying the above result we get:
[tex]\text{Perimeter}=96in\text{.}[/tex]Answer:
[tex]96in\text{.}[/tex]