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
300 square feet
340 square feet.
1,000 square feet.
108 square feet
165 square feet
A total of 160 square feet.
The answer is 270 square feet.
204 square feet.