Ok so go here
https://en.wikipedia.org/wiki/List_o...on_resolutions and sort the column so you see all the 4:3 resolutions which are perfect for EQ. You need to pick something where both values are smaller or equal than your widescreen.
1440×1080 looks like it would go fine on your screen, if you want some padding you can go with 1400x1050. That's for perfect 4:3, but in reality you can be a little off to fit better on screen if you need to, like 1400x1020 would be perfectly fine.