Answer: the barrel can hold additional 72 gallons of water.
Explanation:
The formula for determining the volume of the cylindrical barrel is expressed as
Volume = πr²h
Where
r represents the radius of the cylindrical barrel.
h represents the height of the cylindrical barrel
π is a constant whose value is 3.14
From the information given,
Diameter = 2.5 feet
Radius = diameter/2 = 2.5/2
Radius = 1.25 feet
Height = height = 3.5 feet
Volume of barrel = 3.14 × 1.25² × 3.5
= 17.17 ft³
The height of water in the barrel is 1.5 ft. It means that the volume of water in the barrel is
3.14 × 1.25² × 1.5 = 7.56ft³
The additional volume of water that the barrel can hold is
17.17 - 7.56 = 9.61 ft³
1 cubic foot = 7.481 gallons
9.61 cubic foot = 9.61 × 7.481
= 72 gallons