What is the area of a regular octagon with a side of 8 in. round to the nearest tenth, show work

Length of each side of a regular octagon = 8 inches
We already know the formula for finding the area of a regular octagon as
Area = 2 (1 + square root 2) * (Side)^2
         = 2 (1 + 1.414) * (8)^2
         = 2 (2.414) * 64
         = 308.99 inches ^2
         = 309 inches ^2
So the area of the regular octagon having sides of 8 inches is 309 square inches. This is the easiest method for solving these kind of problems.

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.