3:2 and 4:3 equivalent how?

Detail Man wrote:

ExifTool reports the image-width and image-height of an E-M5 ORF RAW image-file recorded with 4:3 aspect-ratio as 4640x3472 - representing only a 0.694% increase in width and a 0.463% increase in height (relative to 4608x3456).

The corresponding diagonal pixel-dimension is only 0.579% larger in value as a result.

Using the 3.73 Micron pixel-pitch that published DxOMark information lists for the Olympus OM-D E-M5, the (diagonally-referenced) Focal Lengths are the following proportions (as compared to the 43.267mm diagonal of a 36mm x 24mm 35mm film frame-size divided by a Crop Factor of 2.0).

1.009248 times Focal Length for 4608x3456

1.003118 times Focal Length for 4640x3472