Step-by-step explanation:
I think we are missing some information (angle F or B or a side length would be great).
but just the right angles are not enough to calculate specific numbers. they would depend on the angle F or e.g. the side length of AB.
without any further information F and AB can be freely changed without changing the known facts, but it changes also C, B, G
so, all I can say is C = 180 - B.
and that G = B.
The percentage of Change in time is an decrease
If $2397 is 100%
and $685 is unknown
685x100=68500
68500/2397=28.5774
round to 29%