Here is the regular octagon with one apothem drawn in red:Area = (apothem)(perimeter) The area is given as 770 inē. The perimeter is 8 times 12.6 in or 100.8 in. Replacing "Area" by 770, perimeter by 100.8 in Area = (apothem)(perimeter) 770 = (apothem)(100.8) Multiply the by the 100.8 getting 50.4 770 = 50.4(apothem) Divide both sides by 50.4: = apothem 15.27777778 = apothem To the nearest whole number 15 inches. Edwin