What is the required amount of concrete in cubic yards for a foundation wall that is 10" thick, 9' high, and 20' long?

To determine the required amount of concrete for the foundation wall, you will need to calculate the volume in cubic feet and then convert that volume into cubic yards.

First, calculate the dimensions in consistent units. The thickness of the wall is given as 10 inches, which can be converted to feet:

10 inches ÷ 12 inches/foot = 0.8333 feet.

The height of the wall is already given as 9 feet and the length is 20 feet. Now, you can calculate the volume of the wall using the formula for volume, which is height × length × thickness:

Volume = height × length × thickness

Volume = 9 feet × 20 feet × 0.8333 feet

Volume = 150 cubic feet.

Next, to convert cubic feet to cubic yards, use the conversion factor that there are 27 cubic feet in a single cubic yard:

Volume in cubic yards = Volume in cubic feet ÷ 27

Volume in cubic yards = 150 cubic feet ÷ 27

Volume in cubic yards ≈ 5.5556 cubic yards.

Rounding this number gives approximately 5 2/3 cubic yards, which aligns with the choice given. This calculation confirms that the