The answer is true.
Let's say we are calculating the volume of a grain silo where the the width is a constant, but the height can be changed.
In our code we would calculate the volume using something like:
PI * (WIDTH / 2)^2 * height
The variables in all caps would be named constants. Using them makes the code more readable to other people than if we were to just use their values like:
3.14 * (145.75 / 2)^2 * height
