That depends on the depth of gravel. I am going to assume 3 inches of gravel. One 'yard' really means a cubic yard in this context, which is volume.
V = Area of base x depth
7 = (A/9)(3/36) ---- A = 7(12)(9) = 756 sq ft
6.666666666666666666666666666666666666666666666666 yards.
30 ft
20 yards
You cannot convert sq ft into yards, you must convert sq ft into sq yards. There are 9 sq feet in 1 sq yard so there are 283.33 sq yards in 2550 sq ft.
a yard = 3 ft therefore 96 ft = 96/3 = 32 yards
3" inch depth covers 108 sq ft so 450 sq ft and 3" depth = 4.5 yard aprx
2 yards
150 ft
I think you mean 6 inches thick, not 6 feet thick. You would need 200 cubic feet, or 7.4 cubic yards.
23 yards
Based on sand and gravel calculator found on L.R. Faulk Construction Co. site, 1 ton of gravel (clean rock) will equal approximately 7.3 sq. ft x 6 inches deep, or 5.2 sq. ft x 3 inches deep. A ton of gravel will cover approximately 15 square yards (135 square feet) at 3 inches deep.
1500 sq ft = 1500/9 ie 166 2/3 sq yds
4 1/3 squared is .. about 19 square yards
At 12" depth, 20 tons of gravel will cover 360 sq ft.
13 X 16 divided by 9 = 23.11 square yards
6 sq. yds
20 feet x 20 ft x .3333 ft = 133.33 cubic feet / 27 cubic feet per yard = 4.94 cubic yards