I read an article about Babylonian pi. https://numberwarrior.wordpress.com/2008/12/03/on-the-ancient-babylonian-value-for-pi/
The author wrote that Babylonians used 25/8 as pi. But, he could not show the tablet for copyright reasons. He gave some link for the tablet. But, they were not available now.
Is there someone who knows the picture of the tablet?
The tablet is YBC $7302$; it’s in the Peabody Museum of Natural History and can be seen here. It (and much else) is discussed in Christine Proust, Floating calculation in Mesopotamia [PDF], Cuneiform Digital Library Preprints; see pp. $15$ and $16$. It appears that the calculation actually uses the approximation $\pi\approx 3$. This appears to be the generally accepted interpretation of the tablet.