It is not possible to answer this question since a 40 foot octagon could be extremely long.
7??
225 square feet
1,000 square feet.
108 square feet
None. Square feet is a measure of area. A foot or feet measure length.
7??
The answer is 1931,37 square feet.
There is nothing in the question to indicate that it is a regular octagon and since that cannot be assumed, there is not enough information to calculate its area. Even if it were regular, the answer will depend what the 8-foot measure refers to: the length of a side of the octagon, its diameter, its apothem etc.
225 square feet
340 square feet.
300 square feet
1,000 square feet.
108 square feet
The answer is 270 square feet.
165 square feet
A total of 160 square feet.
204 square feet.