mathamatical question help

XR-351 · 22-11-2007, 07:31 PM

hey people, im after a little help,
we want to build a square shed in the corner of our paddock, our paddock is not square and all the fence lines are on different angles which are unknown.

we are able to find one line to work off which is A (which can be any length atm)

how do we work out the rest of the lines if we want them all square angles?

i know it sounds confusing as so i drew a diagram which is probly just as confusing but if any one knows how to work it out it will be a great help

Poorboy_racer · 22-11-2007, 07:40 PM

If A is 10m and B is 10m the diagonal will be 14.142m and at 90 deg. If you have one straight line then you should be able to get another line at right angles. Then work from there. If you can give a Google earth referance I can draw a square shed on the site for you.

XR-351 · 22-11-2007, 07:42 PM

ah cant get close enough but that sonds rite to me, i new it was something like that but couldnt remember the sizes to use

XR-351 · 22-11-2007, 07:43 PM

btw thankyou ill go try it

cuz · 22-11-2007, 07:47 PM

Basic stuff buddy...

A=3
B=4
C=5

Do this and it will ALWAYS be a right angle triangle.

cuz · 22-11-2007, 07:51 PM

If you have a straight line then you can simply measure off that line to get 2 parallel lines.
Any box that is square will have the same length diagonal measurements.
Its hard to explain but easy for me to show you how.

XR-351 · 22-11-2007, 08:03 PM

thanks mate thats also what i thought but i was going off 5 8 10 but same thing, anyway i was just doing it like the to prove a point i know what you mean by doing it the other way
thanks guys for the help

rodderz · 22-11-2007, 08:09 PM

Always use this for work in setting up paving areas etc to be parellel to the house etc, a simple 3,4,5 triangle, or you can double/half those figures to suit the size of the area you need to square up

**Falcon Coupe** · 22-11-2007, 08:12 PM

Quote:

Originally Posted by rodderz

Always use this for work in setting up paving areas etc to be parellel to the house etc, a simple 3,4,5 triangle, or you can double/half those figures to suit the size of the area you need to square up

Yep, we use 3,4,5 method to square up house frames.
Can't trust the concretors to get it right.

:

cuz · 22-11-2007, 08:26 PM

Quote:

Originally Posted by Falcon Coupe

Yep, we use 3,4,5 method to square up house frames.
Can't trust the concretors to get it right.

:

Hey! Thats not on! Leave concretors alone!
I wanted to be one but Mum said I wasn't allowed to have half my brain cut out!!

tpintas · 22-11-2007, 09:18 PM

Guys, Pythagoras' theorum is great, but in the real world

If both pairs of parallel lines are of the same length (each pair for a rectangle, or all four for a square), then you would measure the diagonals, and if they are equal, then all corner angles have to be right angles.

I hope this is easier and helps

cuz · 23-11-2007, 10:07 AM

Quote:

Originally Posted by tpintas

Guys, Pythagoras' theorum is great, but in the real world

If both pairs of parallel lines are of the same length (each pair for a rectangle, or all four for a square), then you would measure the diagonals, and if they are equal, then all corner angles have to be right angles.

I hope this is easier and helps

Hmmm.... So you mean something like this in my earlier post?

Quote:

Originally Posted by cuz351

If you have a straight line then you can simply measure off that line to get 2 parallel lines.
Any box that is square will have the same length diagonal measurements.
Its hard to explain but easy for me to show you how.

Pythagoras' theorum is: A squared + B squared = C squared. Much too hard to explain in a forum.
In the real world its much easier to use the tried and true 3,4,5 triangle, this way you don't need a math degree to understand what you need to do.
Nice try tho...

EA2BA · 23-11-2007, 10:16 AM

Its very very simple.

If each of the opposing sides are 100% the same length, then make sure your diagonals are 100% equal to each other. It is then 100% square to itself. very easy.

EA2BA · 23-11-2007, 10:17 AM

Quote:

Originally Posted by tpintas

Guys, Pythagoras' theorum is great, but in the real world

If both pairs of parallel lines are of the same length (each pair for a rectangle, or all four for a square), then you would measure the diagonals, and if they are equal, then all corner angles have to be right angles.

I hope this is easier and helps

Exactley, I didnt read all the posts first

:

xbgs351 · 23-11-2007, 12:16 PM

Quote:

Originally Posted by cuz351

If you have a straight line then you can simply measure off that line to get 2 parallel lines.
Any box that is square will have the same length diagonal measurements.
Its hard to explain but easy for me to show you how.

At least someone gets it.

The 3,4,5 method is just one possibility obtained from Pythagoras' Theorum and hence for the majority of right angled triangles, the 3,4,5 method is completely useless.