I am used to a 27" 1920x1200 monitor. Roughly what resolution compares to that in terms of image and text size for a 24" panel?
What size widescreen monitor is roughly equivalent to a 19" CRT?
1920x1200 = 16:10 ratio. (16 horizontal inches/cm/whatever per 10 vertical ones)
let theta be the angle such that it is opposite the 10 and adjacent to the 16.
tan(theta) = 10/16
theta = arctan(10/16) = 32.005 degrees.
Y = vertical length
X = horizontal length
sin(theta) = Y/Hyp
Y = Hyp*sin(theta) = 27*sin(theta) = 14.3 inch
cos(theta) = X/Hyp
X = Hyp*cos(theta) = 27*cos(theta) = 22.9 inch
1200 pixels / 14.3 inch vertical = 83.9 pixels/inch
1920 pixels / 22.9 inch horizonal = 83.8 pixels/inch
Rounding errors are probably the cause for the minute difference between the two.
Q: at what resolution would a 24 inch panel have similar text size?
A: Assuming you meant a 16:10 24 inch panel (it matters) then:
theta = arctan(10/16) = 32.005 degrees.
sin(theta) = Y/Hyp
Y = Hyp*sin(theta) = 24*sin(theta) = 12.7 inch
cos(theta) = X/Hyp
X = Hyp*cos(theta) = 24*cos(theta) = 20.4 inch
you are aiming at 83.8 to 83.9 pixels per inch, lets go with 83.85 for consistency, we use the equation a bit differently this time.
A / 12.7 inch vertical = 83.85 pixels/inch
A = 12.7*83.85 vertical * pixels * inch/inch = 1064.895 vertical pixels ~ 1065
B / 20.4 inch horizonal = 83.85 pixels/inch
B = 20.4*83.85 horizontal * pixels * inch/inch = 1710.54 horizontal pixels ~ 1711
So your 24 inch 16:10 panel (likely with native resolution of 1920x1200) needs to be set to a resolution of 1711:1065 to have identical text/picture size to your 27".
since you don't want distortion (the figures above are not exactly 16:10 due to rounding errors) you must maintain your aspect ratio, take 1065 * (16/10) and you get 1704... so its better use 1704:1065.
but I wouldn't recommend running at such an odd resolution at all. 1680:1050 is a standard resolution and makes more sense to run. it will be ever so slightly bigger.