CGA was 640x200 in 4:3, which matches your circle.
EGA was 640x350 in 4:3, so your circle would need to be 480x350 or 274x200 unless you ran the EGA in a CGA mode.
Hercules was 720x348.
(Score: 0) by Anonymous Coward on Thursday March 11 2021, @08:59AM
CGA was 640x200 in 4:3, which matches your circle.
EGA was 640x350 in 4:3, so your circle would need to be 480x350 or 274x200 unless you ran the EGA in a CGA mode.
Hercules was 720x348.