[CentOS] 1600x900 not available

Wed Jan 10 14:43:08 UTC 2018
Sean Smith <stoc2528 at gmail.com>

My laptop is a Dell XPS-13 running CentOS 7.  It has a 13" 1920x1080 
screen and it's a bit difficult for my mid-40s eyesight.  Fedora and 
Debian, on this laptop, give me the option of choosing 1600x900 which is 
much easier for me to read but CentOS doesn't show this resolution as 
available.

I followed the steps I found in a post on stackexchange using xrandr, 
substituting 1600x900 where applicable and it worked but, once I 
rebooted, it went back to 1920x1080 with no 1600x900 option in 
settings-display.

Is there a way I can add 1600x900 resolution the list of available 
resolutions in settings-display?

Thanks,

Sean