Why is Gnome fractional scaling 1.7518248558044434 instead of 1.75?

If I set 175% scaling in Gnome Settings, the value is saved as 1.7518248558044434 in ~/.config/monitors.xml:

0
      0
      1.7518248558044434
      yes
      
        
          DP-3

Why is it so? At first, I thought it could be due to floating point rounding error, but 1.75 is one of those happy numbers whose the exact value can be expressed. Gnome Wayland 43.3