Yep. So the corners, especially on an irregular footprint building, have to get determined somehow so that they are all square to each other. What tool is used to do that, regardless of how complex the footprint is.
Answer: Pythagorean’s Theorem and a calculator with a square root function.
Give me those tools (I’ve long forgotten how to calculate the square root of a number by hand, so I need a hand calculator with a square root function) and I’ll tell you exactly where all the corners should be on any block job. Exactly.
It’s like the 3-4-5 rule only it works for anything. The diagonal between corners is simply the square root of the sum of the squares of the sides.
And that’s why 3-4-5 works:
3 squared (3x3) is nine. 4 squared (4x4)is 16. 9+16=25. The square root of 25 is 5.
Anyway, Pythagorean’s Theorem works every time with any distances, any numbers, any units. With it you can pinpoint any corner location exactly and easily and it will be square with the other corners, regardless of how complex the building footprint.
Transit - Transit levels are used mainly for surveying and building, but they can be used to determine the relative position of lines and objects as well.
Anyone remember learning to use the “slide rule”? Or was it just me!
Calculator…square root.
Yep.
Not just you!
Still own a couple… One of them My Grandad’s which he used whilst working at “Shawinigan Electric”…
It’s been a while since I’ve used it and it would probably take me a few minutes to remember all the functions! 
So now we are not talking about a building that is “square” per se.
While there is some correlation between Algebra and Geometry, the Pythagorean theorem only works in a right angled triangle. That said, a RAT can be used to create any other shape.
There are a number of tools you could use, handed down over centuries of masonry. Linear measure, masons square (3-445), folding layout ‘A’ Square, compass.
The footprint, totally irregular, would still be a combination of squares, rectangles, triangles, circles and arcs. The only squaring would be required if a right angled triangle was required in the footprint.
Now you would need to calculated the square root for the lengths.
As for calculating the square root without a calculator (lets take 7.65)
Find an integer whose square is less than or equal to the first number (or pair in the single number cannot be rooted by an integer).
2x2 = 4 and 3x3 = 9. 9 is higher than 7 so the number we need is 2
This is the first number in the answer.
You then subtract the square of that number from the group you used (in this case 7. 7-4 = 3)
Tag on the next two numbers (gives you 365)
Double the number you first got ( 2 doubled = 4)
You now need to find 4a X a < 365. In out case a would be 7 so 47 x 7 = 329.
Take 329 from 365 and you get 36. Now your square root so far is 2.7.
Tag on the next two numbers (00 because there are no more) and this gives you 3600.
Double the 27 (gives you 54) and you now need to establish what 54a x a is less than 3600. In our case it’s 6 which gives you 3276. So we now have the square root to 2 decimal places at 2.76.
Repeat the process. 3600-3276 =324, tag on next two numbers (00) to give 32400. 276 X 2 = 552. 552a x a < 32400. This time it’s 6 ( 5526 x 6 = 27,625) No we have a square root of 2.765 to 3 dec. places.
Keep going until you either get a finite finish of a recurring number. In our case it ends up as 2.765863337187866666666 rec. Although in a building I’ve never had to think of anything smaller that I could measure, so 2.765 would have been fine, and i would have probably settled for 2.75 and a bit more mortar somewhere.
While I would agree it’s Waayyyyyy easier with a calculator, Pythagoras didn’t have one, and it’s not a bad mind tool to keep all your marbles going.
Also when you are in the middle of the North Yorkshire Moors, it’s raining stair-rods and the battery on your calculator, which is now soaked has just gone kaput, it’s good to know how to do it the old way. 
I’m going to bed now because my brain hurts.:mrgreen:
Absolutely loved the slide rule. I was lucky enough to have a Full size Keufful & Esser. Saw me through school, college and flight training. Lost it in my 1st divorce. Probably worth a fortune now.
Me to.
Took technical drafting in high school.
Sat on fathers lap as he drafty endless when I was very young.
He was an industrial electrical engineer at GE.
Thanks, Nick.
Len, what I lost during my divorse saved me a fortune.
I like robotics and from what I read they are here to stay and make life easier for me and others .
Like my Lawn mower so much bought a second one . Six years and all I have to is trim the edge .
I like robotics and from what I read they are here to stay and make life easier for me and others .
Like my Lawn mower so much bought a second one . Six years and all I have to is trim the edge .
Are they combustion or electric?
If electric, how long is the charge good for? Can it do the entire property without needing a reload?
24 volt electric first Cost $1800’00 Canadian eight not six years error in the first letter ago yes does the whole yard .
Second cost $1500’00 USA 6 years ago . they no .No longer make this model .
It has a parking station and charges the battery . You can set how often to do the grass and it does it automatically goes home if it starts to rain . .
Has a single strand Ariel wire around the edge to keep it in the yard
new model http://usa.robomow.com/
Good way of looking at it. I should have 2 fortunes now.
Bit like battery powered sheep.
I have a Irobot Roomba vacuum that I really like.