A 1/4 min adjustment at 100 yards is also a 1/4 min adjustment at 200, 300, 400 and everything else down range.
If your asking what that value in Inches would be then its a different story. Basically 1 minute of angle at 100 yards is something like 1.047".
1/4 min at 100 yards would 0.262" but thats getting pretty finite. Most simply figure 1/4 min is roughly 1/4" at 100 yards.
As the range increases so does the "inch" value of a minute of angle in multipuls of the range you are increasing by.
For example, 1/4 min at 100 yards is roughly 1/4".
1/4 min at 200 yards is roughly 1/2"
1/4 min at 300 yards is roughly 3/4"
1/4 min at 400 yards is roughly 1"
Now remember this is a rough estimate but close enough for most work. At extreme range it can make a larger difference. It simplifies things much more just to convert to MOAs then to try to figure exact "inches" of adjustment at longer ranges.
Kirby Allen(50)