Final answer:
To find the volume of concrete needed for the patio, convert the dimensions from feet to yards and use the formula for volume. You would need to buy approximately 20/9 cubic yards of concrete.
Step-by-step explanation:
To find the volume of concrete needed for the patio, we first need to convert the dimensions from feet to yards.
Since 1 yard is equal to 3 feet, the dimensions of the patio in yards would be 12/3 = 4 yards by 15/3 = 5 yards.
Next, we need to calculate the volume of the patio in cubic yards.
The formula for volume is length times width times height. The height of the patio is given as 4 inches, which is equal to 4/36 = 1/9 yards.
Therefore, the volume of the patio is 4 yards * 5 yards * 1/9 yards = 20/9 cubic yards.
So, you would need to buy approximately 20/9 cubic yards of concrete for the patio.