who invented PI

Euclid, I think.
A quick Google search also suggests it was Euclid.

A quibble, I know... but nobody "invented" Pi , its not something to be invented. Now , who was the first to UNDERSTAND Pi and to figure its parameters we'll probably never know but its approximate value has been know and used for a very long time : ...."The Egyptian scribe Ahmes wrote the oldest known text to give an approximate value for Pi, citing a Middle Kingdom papyrus"...... ." "By 2000 B.C., Babylonians established the constant circle ratio as 3-1/8 or 3.125. The ancient Egyptians arrived at a slightly different value of 3-1/7 or 3.143"...... not far off and considering, not too bad.

Correct, π was a discovery that the ratio of a circle's circumference to its diameter is constant regardless of the length of the diameter. 22/7 is an approximation.
Newton didn't invent gravity either, he discovered it, although that may be a myth.

A Guy

Many year ago I read that PIE might of been realized when pouring sand into a pile. The little pointed cone that was created always had the same angles and measurements when done in the same fashion. They thought of that as one of the natural structures of the gods.

Layback Bear said:

Many year ago I read that PIE might of been realized when pouring sand into a pile. The little pointed cone that was created always had the same angles and measurements when done in the same fashion. They thought of that as one of the natural structures of the gods.

I think you are thinking of the Angle of Repose

eee the boffins are awake. dont rattle the cage!

pie was invented by apple

Could be, it's been a long time. I stand corrected.