I remember some of a method my dad used to layout a foundation when he was
building a house.   I can only remember part of the method where he
measured 3 ft on on side of the corner and 5ft the other side of the corner
and he calculated a number and would measure that distance as a 45 degree
angle between the 3 and 5 foot marks he had made.  He would have one corner
fixed and the other he would move the calculated distance and the corner
would be square. Some of my recollection maybe wrong as it has been decades
since I have seen this done so please correct me where needed.

Can someone who is familiar with this layout method please tell me how to
do it.  If you have a better of easier method than the one I described
please post to this so we can get a practice field laid out for our high
school marching band to practice on.

Thanks Douglas V Stone
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On 7/18/2012 8:52 PM, Douglas Stone wrote:
> I remember some of a method my dad used to layout a foundation when he was
> building a house.   I can only remember part of the method where he
> measured 3 ft on on side of the corner and 5ft the other side of the corner
> and he calculated a number and would measure that distance as a 45 degree
> angle between the 3 and 5 foot marks he had made.  He would have one corner
> fixed and the other he would move the calculated distance and the corner
> would be square. Some of my recollection maybe wrong as it has been decades
> since I have seen this done so please correct me where needed.

Doug, I'm sure I'll be one of many to respond...Just use Pythagoras' 
Theorem (a-squared + b-squared = c-squared).  Here's a site that 
explains it:
http://www.mathsisfun.com/pythagoras.html

A right angle (90 deg) can be laid out by establishing your base line 
and then run another line more or less perpendicular to it.
Measure and mark 3 feet (inches, meters, millimeters...whatever your 
unit of measurement is) along the base line from the intersection of the 
two.
Measure and mark 4 units from the intersection on the perpendicular line.
Place one end of your measuring device on the 3 mark and lay the body of 
the device on the 4 mark.  Adjust the line with the 4 mark on it until 
it fall directly on the 5 mark of your measuring device.
You now have a 90 degree corner.

If you're laying out a 90 degree angle on paper, the Old Millwright has 
explained it better than I can so I imagine he'll chime in and point you 
to his 'how-to'.  I think it's on Wiktor's site but then my memory isn't 
what it used to be ;-)
Charlie Rodgers
Clinton, Maryland

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On 7/18/2012 9:05 PM, Charlie Rodgers wrote:
> On 7/18/2012 8:52 PM, Douglas Stone wrote:
>> I remember some of a method my dad used to layout a foundation when he
>> was
>> building a house.   I can only remember part of the method...
snip
>> since I have seen this done so please correct me where needed.
>
> Doug, I'm sure I'll be one of many to respond...Just use Pythagoras'
> Theorem (a-squared + b-squared = c-squared).  Here's a site that
> explains it:
> http://www.mathsisfun.com/pythagoras.html

Doug, I realize it's poor form to respond to my own post, but I forgot 
another tip that may come in handy.
After you lay out the field, measure diagonally (criss-cross) from 
corner to corner.  When the measurements are equal, you have a rectangle 
with four 90 degree corners (instead of a parallelogram).

Charlie, who actually enjoyed plane and solid geometry in school...

------------------------------------------------------------------------

> 
> Doug, I realize it's poor form to respond to my own post, but I forgot another
tip that may come in handy.
> After you lay out the field, measure diagonally (criss-cross) from corner to
corner.  When the measurements are equal, you have a rectangle with four 90
degree corners (instead of a parallelogram).

Provided only that the 4 sides are equal.

James Thompson, the oldmillrat

Of all the things I have ever lost, I miss my mind the most.

------------------------------------------------------------------------

On 7/18/2012 9:38 PM, James Thompson wrote:
>>
>> Doug, I realize it's poor form to respond to my own post, but I forgot
another tip that may come in handy.
>> After you lay out the field, measure diagonally (criss-cross) from corner to
corner.  When the measurements are equal, you have a rectangle with four 90
degree corners (instead of a parallelogram).
>
> Provided only that the 4 sides are equal.
>
Jim's right.  If you're talking about a square (four equal-length 
sides), the diagonals will be the same length.  But not only in a square.
   I thought that a practice field would likely be a rectangle.  The 
diagonal measurements will also be equal in a rectangle.
Charlie Rodgers
Clinton, Maryland

------------------------------------------------------------------------

>   I thought that a practice field would likely be a rectangle.  The
> diagonal measurements will also be equal in a rectangle.

Necessary, but not sufficient.  For example, a symmetric trapezoid
will also have equal diagonals and the corners are not necessarily
right angles (Galoot version: imagine a four sided figure with a 2
inch top parallel to and centered over a 4 inch bottom (2 cm top over
a 4 cm bottom, Jeff)).

Joe Parker, Ph.D. Mathematics, 1976
------------------------------------------------------------------------

http://www.sportsknowhow.com/football/field-dimensions/nfl-football-field-dimensions.html
a little trig will carry our corners out square

On 7/18/2012 8:52 PM, Douglas Stone wrote:
> I remember some of a method my dad used to layout a foundation when he was
> building a house.   I can only remember part of the method where he
> measured 3 ft on on side of the corner and 5ft the other side of the corner
> and he calculated a number and would measure that distance as a 45 degree
> angle between the 3 and 5 foot marks he had made.  He would have one corner
> fixed and the other he would move the calculated distance and the corner
> would be square. Some of my recollection maybe wrong as it has been decades
> since I have seen this done so please correct me where needed.
>
> Can someone who is familiar with this layout method please tell me how to
> do it.  If you have a better of easier method than the one I described
> please post to this so we can get a practice field laid out for our high
> school marching band to practice on.
>
> Thanks Douglas V Stone
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------------------------------------------------------------------------

Hi

Pythagoras as stated allows one to create a right angle - the most simple is
a 3 - 4 - 5 triangle - but it will work with multiples e.g. 6 - 8 - 10 as
the unit of measurement doesn't matter (inches, feet, yards, mikes).

Carpenters often used to use a knotted string 12 ft long - with a knot or
small loop at each end and also at the 3ft and 7ft points. Three nails or
pegs allowed one to set out a right angle when all three sides of the
triangle were taut (note: you need a string that will not stretch).

For a football pitch you may be better with a 12 yard length....

Lay out a baseline AB with two pegs and a length of string between them,
then at each end mark out a right angle with the knotted cord, and extend
the string around the two pegs to points C and D (C follows B and D is from
A). Measure the length AD and BC and place two more pegs at C and D - you
now have your four corners. To check it is square you can measure the
diagonals AC and BD - they should be the same...

If you do not have string long enough, you can do the same thing with
ranging poles - set out two poles, and a third between them on one end of
the knotted cord. Line up the third pole until it is in line with the first
two, tension the cord, and place a fourth pole at the other corner of the
triangle - you have now set up a right angled corner - with a fifth pole you
can determine the third corner of the pitch and so on...

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