Rhode Island Journeyman Plumber Practice Exam 2026 - Free Journeyman Plumber Practice Questions and Study Guide

To determine how many gallons of water are in a cylindrical tank, you can use the volume formula for a cylinder, which is:

Volume = π × r² × h

In this equation, r is the radius of the cylinder, and h is the height. Since the tank in question is 24 inches round, the diameter is 24 inches, giving a radius of 12 inches (half of the diameter). The height of the tank is given as 60 inches.

First, calculate the volume in cubic inches:

1. Convert the radius to inches:

r = 12 inches

2. Plug the values into the formula:

Volume = π × (12 inches)² × 60 inches

Volume = π × 144 inches² × 60 inches

Volume = π × 8640 inches³

3. Approximate π as 3.14 for a quick calculation:

Volume ≈ 3.14 × 8640 ≈ 27154.4 cubic inches.

Next, convert cubic inches to gallons. There are 231 cubic inches in one gallon.

4. To convert, divide the volume in cubic inches by 231:

Volume in gallons ≈ 27154