Answer: the volume of concrete to be used is 753.6 ft³
Step-by-step explanation:
Since the columns are cylindrical, we would determine the volume of each column by applying the formula for determining the volume of a cylinder which is expressed as
Volume = πr²h
Where
π represents a constant whose value is 3.14
r represents the radius of the columns
From the information given,
Diameter = 4 feet
Radius = diameter/2 = 4/2 = 2 feet
Height = 20 feet
Volume = 3.14 × 2² × 20 = 251.2 ft³
Volume of the 3 concrete columns is
251.2 × 3 = 753.6 ft³