If you are referring to 27' 9" head of water at 39.2F, then the pressure will be 12.0158 pounds per square inch at the base.
1 ft. of head x 0.433 = pressure in lbs/sq.in.
0.006944... square feet.
736 square inches /144 = 5.111+ square feet, or 5 square feet 16 square inches
A square of 17.5 inches by 17.5 inches is 2.13 square feet.
1,008 square inches = 7 square feet.
106 square inches = ~0.74 square feet.
432 square inches = three square feet.
100 square inches = 0.69444 square feet
200 square inches are 1.39 square feet.
1,600 square feet = 230,400 square inches.
10 square feet = 1,440 square inches.
1,440 square inches are in 10 square feet.
6,224 square inches is 43.22 square feet.