chord durations

[Christian Henning]

Hi there, adding a dot to a chord duration prolongs it by 50%. "g4.",
for instance, is 1.5 beats or three 8th notes. "g4.." is 1.75 beats, I
believe. Which would translate into seven 16th notes. But what is
"g4..."? Here, with 3 dots.

Also, how can I describe a duration that lasts for 2.25 beats?

I realize that I don't really ask lilypond related things but more
general music theory questions. I'm hoping this community is still
kind enough helping me out.

Thanks,
Christian