First you need to understand that the "yard" of material is really a cubic yard (3 x 3 x 3) or 27 cubic feet. Each cubic foot is 12 inches by 12 inches by 12 inches.
you begin by multiplying the 15 foot width by the 55 foot length. (15 x 55 = 825) If you assume that you have a 12 inch high fill then all you have to do is divide 825 by 1/4(3 inches) to get the number of cubic feet of top soil. divide again by 27 to get the number of cubic yards.
if that is 3 ft deep it would require 96 yards... IF it is 3 inches deep it would require 24 cubic yards
62/3 cubic yards for every 1-foot deep. 5 cubic yards for every 9-inches deep. 31/3 cubic yards for every 6-inches deep. 5/9 cubic yard for every 1-inch deep.
That's 13 cubic yards of mulch for every 2 inches deep.
15.833... [cubic] yards.
.21 yards of sand will fill an area 115 inches by 67 inches to a depth of 2.5 inches.
You will need about 463 cubic yards (around 594 tons) of gravel for this area.
2.37 cubic yards of stone for every 3 inches deep it needs to be
tweleve
1 cubic yard will cover 15 square yards at 3 inches deep.
You would need about 13 cu yards or about 15 tons.
105 ft * 84 ft * 3 inches = 105/3 yards * 84/3 yards * 3/36 yards = 35 * 28 / 12 cubic yards = 245 cubic yards.
Usually a cubic yard will cover 15 square yards at 3 inches deep so I would reckon on 22 cubic yards. Hold on that I've got that wrong it's 2 cubic yards .Sorry.