garden fence at right-angle to house

================================== Get a large sheet (6' x 2')of chipboard or an old door and lay it flat with one short edge along the wall of the house. Use this board as a 'square' and run a string line along side it to give you a straight line at 90 degrees to your houses.

Cic.

Apply the old 3,4,5 rule. 3 foot along wall, 4 foot along fence and 5 foot for the hypotenuse to make the right angle.

Or for a more accurate measurement, use Pythagoras's theorem. Lay a 3 unit length against the wall, a 4 unit length as the boundary guide, and a 5 unit length to make up the other side of the right angled triangle.

"john westmore" wrote in news:g4v26i$uvp$ snipped-for-privacy@registered.motzarella.org:

What!

As others have said, the 3:4:5 triangle with a bit of string will do that.

However, it doesn't mean that it is necessarily the right place for the fence.. With any luck, if you toddle up the garden you may find the (remains) of the boundary marker. Which may be just a small wooden post in the ground.

The original builders may not have been that precise with the right angle as you seem determined to be. Your neighbour may not be too happy if your efforts leaves the boundary post well and truly your side of the fence.

-- Sue

The OP is in the UK, and the EU has forced them to use metres for measurements. Of course this changes everything. If he wants to use

Yep. I'm in Oz. Down here we use the 4 side on the wall.

I think I could do that one in my head, let me think now, yes I think I have got it, the hypotenuse would be 5 metres. ;-)

As others have suggested, use the 3,4,5 rule (it's what the builders of the pyramids in Egypt did).

If the houses are 20 meters apart, you can use 15, 20, 25 meter measurements.

However there's one difficulty you may encounter. The wall may be square to one house and crooked as a dog's hind leg at the other.

I recommend bushes.

Weird.... I thought the pyramids pre-date Pythagoras by 1 or 2 millennia?

And your point is?

If I may, as the same thought occurred to me, I believe his point is that the 3,4,5 rule, commonly referred to as the Pythagorean theorem, is credited to Pythagoras. It's difficult to use concepts that have not yet been developed.

Obviously there is a hell of a lot we don't know about the state of technology on Earth at the time the pyramids were built.

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================================== Doesn't that just make a large set square - something like a rectangular board with squared corners?

Cic.

Smitty Two wrote: ...

Well, of course, it was them extra-terrestrials that showed them the points from their higher vantage point...

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They had been developed - just not fully explored and understood. And keep in mind that it's quite possible to develop and use a mathematical formula but not to have a proof or deeper understanding of it.

Uh, they did. But right angles pre-dated the pyramids by at least several decades.

The circle is even older.

They do. And IIRC the Egyptians knew 3,4,5 but not the general rule about the square of the hypotenuse etc. - which is what Pythagoras discovered. Oh hang on...In another source...

This is bad. You'll end up with something 3 times as big as a pyramind.

Good points.

Au contraire, mon ami. At least in this case.

Most of the pyramids did not require the local use of mathematics at all. They were usually built from kits sold by Sears, and all the calculations were done by Sears technicians.

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