Format decimal value to string with leading spaces

Question

How do I format a decimal value to a string with a single digit after the comma/dot and leading spaces for values less than 100?

For example, a decimal value of

Answer 1

Another one with string interpolation (C# 6+):

double x = 123.456;
$"{x,15:N4}"// left pad with spaces to 15 total, numeric with fixed 4 decimals

Expression returns: " 123.4560"