Michigan Residential Builders License Practice Test

How many cubic yards of concrete would you need for a patio measuring 10 feet by 20 feet and 4 inches thick?

1. 2 cubic yards

2. 3 cubic yards

3. 4 cubic yards

4. 5 cubic yards

The correct answer is: 2 cubic yards

To determine the volume of concrete needed for a patio measuring 10 feet by 20 feet and 4 inches thick, the first step is to convert the dimensions to a consistent unit. Since most calculations for concrete are done in cubic yards, you can convert the thickness from inches to feet. There are 12 inches in a foot, so 4 inches is equivalent to \(\frac{4}{12} = \frac{1}{3}\) feet. Next, calculate the volume in cubic feet: 1. Calculate the area of the patio by multiplying the length by the width: \[ \text{Area} = 10 \text{ ft} \times 20 \text{ ft} = 200 \text{ square feet} \] 2. Now, multiply the area by the thickness to get the volume in cubic feet: \[ \text{Volume} = \text{Area} \times \text{Thickness} = 200 \text{ sq ft} \times \frac{1}{3} \text{ ft} = \frac{200}{3} \text{ cu ft} \approx 66.67 \text{ cu ft} \] Finally,