# Question Video: Finding the Volume of a Cylinder in a Real-World Context Mathematics • 8th Grade

Given that about 7.5 gallons of water can fill one cubic foot, about how many gallons of water would be in this cylindrical water tank if it was full?

01:46

### Video Transcript

Given that about 7.5 gallons of water can fill one cubic foot, about how many gallons of water would be in this cylindrical water tank if it was full?

In this question, we have a cylindrical water tank with a diameter of 20 feet and a height of 12 feet. We begin by recalling that the volume of a cylinder π can be calculated by using the formula π is equal to ππ squared β, where π is the radius and β is the height of the cylinder.

The radius of the cylinder is half of the diameter, so this is equal to 10 feet. Since the height is 12 feet, the volume of the tank is equal to π multiplied by 10 squared multiplied by 12. This is equal to 1200π cubic feet.

We are told in the question that 7.5 gallons of water can fill one cubic foot. This means that the amount of water in the tank is equal to 1200π multiplied by 7.5. This simplifies to 9000π. As a decimal, this is equal to 28274.33 and so on, which is approximately 28274 gallons. This is the amount of water that would be in the cylindrical tank if it was full.