How the ancients calculated pi

The ancient Greeks used 25/8(3.125) for an approx. for pi even though they knew 22/7(3.142857...) was closer. That was because eighths were easier to draw. Pi's decimal digit was about .141592653589793238462643383
279502884197169399375105820974944592
307816406286208998628. So during that time the 1/8(.125) was not that far off.