What does the number after the decimal point mean when interpolating in C#?

Question

C++ / C#

I'm going to break down simple examples. Got this example:

double[] array2 = new double[5] { 1.2, 3.4, 5.6, 7.8, 9.10 };

            foreach ( double element in array2 )
            {
                Console.WriteLine($"{element,5}^2 = {element * element}");
            }

I can't understand what is 5 after the decimal point in the loop? {element,5}
I tried to remove the semicolon, it still works)