Answer:
The total area of the pool section of Keith's backyard is 390 square feet.
Explanation:
Since Keith is trying to figure out the area of his pool section in his backyard, and he knows that his pool is 20 feet long and 9 feet wide, and he also knows the sidewalk is 3 feet wide all around the floor, to determine what is the total area of the pool section of Keith's backyard, the following calculation must be performed:
(20 + 3 + 3) x (9 + 3 + 3) = X
26 x 15 = X
390 = X
Therefore, the total area of the pool section of Keith's backyard is 390 square feet.