Is There a Reason Why the Academy Declared Four Three Instead of Square?

In the 19 thirties, the academy decreed that all movies on 35 millimetr film should be made in the so called ad ratio. So at one point three, three to one point three six was the shape of basically every film made in hollywoods between about 19 32 and 19 52 with only a tiny handful of exceptions. The perfect aspect ratio is circle because a lens is a circular, is a circular lens, and it's projecting a circular image.