Question

You need to cover the playground of a child development center with mulch. the playground is 125 feet long and 60 feet wide. you want the mulch to be at least 6 inches deep.how many cubic yards of mulch should you have delivered? round your answer to the nearest whole number.

Answer 1

The answer is 139 cubic yards

This mulch will be of cylindrical shape.
The volume (V) of a cylinder is: 
V = l · w · h           (l - length, w - width, h - height (in our example, height = depth)

It is known:
l = 125 feet
w = 60 feet
h = 6 inches = 0.5 feet

V = l · w · h = 125 · 60 · 0.5 = 3750 feet³

Since 1 cubic foot is 0.037 cubic yards, 3750 cubic feet are 139 cubic yards:
0.037 ·  3750 feet³ = 138.75 cubic yards ≈ 139 cubic yards