The floor is (8 x 12) = 96 square feet
The ceiling is also . . . 96 square feet
Two walls are (8 x 8) = 64 square feet each
The other two walls are (8 x 12) = 96 square feet each
The total inside surface area is (2) x (96 + 64 + 96) = 512 square feet
(including the area of the door, hatch, etc.)
Assuming the 12ft is the diameter of the circle. The formula is A = pi x r2 Pi = 3.14 for general use. Therefore, (6 x 6) x 3.14 = 113.04ft2
12ft x 15ft = 180ft2
2*(length + width) = 54 feet.
32ft x 12ft = 384 square feet which converts to 35.6748 square meters.
Length is 12ft, width is 4 ft. 2 x (length + width) = perimeter = 32 ft ⇒ length = 16ft - width [1] length x width = area = 48 sq ft Using [1] above: ⇒ (16ft - width) x width = 48 sq ft multiplying out and rearranging: ⇒ width2 - 16 x width + 48 = 0 factorizing: ⇒ (width - 4)x(width - 12) = 0 Thus width = 4 or 12, so using [1] above: ⇒ width = 4ft, length = 16 - 4 = 12ft or width = 12ft, length = 16 - 12 = 4ft Convention is that the length is larger than the width, thus rectangle is 12ft long by 4 ft wide.
This needs more information to supply a "best" answer. A 12ft by 12ft patio gives a surface area of 16 sq.yds. A yard of concrete is a cubic yard. The number of cubic yards depends on the thickness of the slab, and the size and depth of foundations (if any). This depends on the type of soil and subsoil, and whether you have very cold winters. If you live in a warm area, 3 yards is probably about right. If you are planning to do this yourself, try asking your local building inspector for his advice.
12 x 12 feet, 4 inches deep: 1.8 cubic yards, minimum.
This cylinder will require 1.4 cubic yards of concrete (this assumes a length of 12' and a width of 2').
864 ft
144 square feet.
15ft
12 x pi (3.14) = 37.68ft2
80 x 80 x 12
Area = 12ft * 12 ft = 144 square feet.
12 * 9 = 108 square feet = 12 square yards
6 x (12 x 12) = 864 sq. feet
None. A foot is a measure of distance while the area of a room is measured in square feet. these are two different measures measuring two different things and it makes no sense to try to convert from one to the other.