23 x 2 x 0.09 = 4.14 m3
The floor is 4 times 288 times 384 cubic inches, or 442,368 cubic inches. 1 inch = 2.54 centimeters. Thus, 1 cubic inch = 2.54 times 2.54 times 2.54 cubic centimeters, or 16.387064 cubic centimeters. So 442,368 cubic inches is 7,249,112.727552 cubic centimeters. Each cubic centimeter is 0.000001 cubic meters (1,000,000 cubic centimeters = 1 cubic meter). So the floor is 7.249112727552 cubic meters. You can essentially call this 7.25 cubic meters. You can also determine from this that a cubic inch is 0.0000016387064 cubic meters, which can be used as a shortcut.
100 mmm = 0.100 meter 28 x .1 = 2.8 cubic meters
4.23776 cubic yards
2x27x0.1=5.4 2x27=54 54x0.1=5.4
Concrete is sold in cubic (volume) measurements not square (area) measurements.
A cubic foot is 12" thick 12" wide and 12" deep. .45 cubic feet per 60# bag of concrete
You will need 17.8 cubic yards of concrete.
It depends upon how thick you want the concrete. For example, if you want the concrete to be 6 inches thick, then you will need 200 cubic feet. There are 27 cubic feet per cubic yard; so divide the 200 cubic feet by 27 to get 7.4 cubic yards.
(3.25 (sq m)) * 20 mm = 0.065 cubic meters
10.67 Cubic Yards
That depends on the length and width of your construction.
20 mm = 0.020 meters 18 square meters * 0.020 meters = 0.36 cubic meters