7,500
26.65 cu .ft.
If a cube measures 5 inches on an edge, then each face of that cube is a square measuring 5 inches by 5 inches, having an area of 25 square inches.
Add up the three dimensions of your box, suitcase, etc. Height plus width plus depth should total 40. Examples include: 15 inches wide, 15 inches deep, 10 inches high = 40 linear inches Also 25 inches wide, 10 inches deep, 5 inches high = 40 linear inches
25 inches
25 cubic inches
There are: 69*36*25 = 2,509 cubic inches
That would be a really wide textbook. Most of them are going to run between 8 and 12 inches. The unit you are probably looking for is centimeters. A book could be 25 cm wide (about 10 inches).
25 inches wide
The volume of 25 inches times 15 inches times 10 inches is 3750 cubic inches.
5x5x6=150 If the cube has 5 inch long sides then each side has an area of 5 inches x 5 inches which equals 25 sqare inches. The cube has 6 sides so the total area of paper needed to cover it is 25 square inches x 6, which is 150 square inches of paper.
25mm = about 0.984 inches.