The 8 sides of the regular octagon are all the same length, so the perimeter of it is 8*(12.4 in) = 99.2 in.
The area of a regular polygon is half the product of the perimeter and the apothem.
area = (1/2)(99.2 in)(15 in) = 744 in²
The area of the stop sign is 744 in².
