‘Are you serious?’
No.
*edit - and making a 3:4:5 triangle is a piece of piss.
Correct. However, using a 3, 4, 5 triangle to accurately set out a grid, baseline or some other form of horizontal plan is not a piece of piss if you are talking about distances larger than a few dozen metres. I've been there - it's one of those things that sound easy but isn't. Discrepancies multiply. To get the lengths of each basal side accurate to within a few inches is pretty astonishing, in my opinion (which is obviously not an expert one). I'm basing the accuracies on some reading I had to do for university, though, so admittedly this was several years ago now and, as you say, the facing stones have gone so the researchers would have been working on estimates. I do remember the egyptology module lecturer impressed on us how much quackery went on with regards to archaeology as a whole, and the pyramids in particular, but he also was of the opinion that the pyramids, as with many large scale Egyptian monuments were really rather astonishing achievements of architecture considering the knowledge and technology they had available.
I've already been over this in previous posts and can't really be bothered again - no offence - but I maintain that the great pyramid, and probably most other pyramids, is an astoundingly impressive feat of human engineering and labour, as with many other large monuments from various ancient cultures across the globe. At the risk of repeating myself, I'm not ascribing any extraterrestrial or mystical influences to their conception or construction, merely saying it's pretty fucking mad what ancient civilizations got up to when they put their minds to it. That's it, the end.