1 [cubic] yard = 27 cubic feet
18 inches = 1.5 feet
Volume of the garden = (8 x 12 x 1.5) = 144 cubic feet = (144/27) = (5 and 1/3) cubic yards
Three acres three inches deep is 403.33 cubic yards.
40.1 cubic yards
2.2222222 cu. yards
3,456 cubic yd.
.617 Yards
259.2593 sq. yards.
6 inches = 1/6 yards. So 70 sq yards * 6 inches = 70*1/6 cubic yards = 11.66... cubic yards.
You would need 31.88 cubic yards of topsoil to cover 855 sq feet at 6 inches deep.
.21 yards of sand will fill an area 115 inches by 67 inches to a depth of 2.5 inches.
You'll need 1.23 Cubic Yards.
2.2 Yards
1.851852 cubic yards