Measurement help?

Question

need to make a rectangle

the length is 39'7 and the width is 15'10 with diagonal measurements at 42'8 (in order to make it a perfect square)

however when I stack out the measurements the diagonal is never 42'8 always like 39'8 or 43'2 but never 42'8, what am I doing wrong?????

Answer 1

Your rectangle is racked.  You need to adjust the side until your diagonals are equal.  That will be square.

You can try to get the diagonal to hit 42' 7-1/2" (the target length of the diagonal), but it's easier just to make the diagonals even.  If one is 2" longer than the other, move your lines 1" to make them even.  Good luck.

Answer 2

Since the diagonals are off, you need to bring the corners together on the long diagonal and apart on the short diagonal until the diagonals match your  42'8" distance. I suspect what has happened is the string is stretching on one side or the other.  It is only a 1/2 or so in any direction to throw the diagonal off that far. In effect your corners are not perfectly square, you have made a rhombus not a rectangle. You could get a longer tape measure.

Answer 3

when you cross measure corner to corner, both ways it should match. then your square. if it don't match split the difference, then it is square.  i start with the 3 4 5  rule. 3ft by 4ft angles 5 ft.

Answer 4

If you're using a typical butt joint then you have to consider the thickness of the wood being used and how it it then added to the length or width (depending on which side the wood was placed. For instance, if you were using 2x4s and added the boards to the existing 39'7" you'd have to add an additional 1.75" to both sides to accommodate for the actual thickness of the 2x4.

As long as parallel sides are of the exact dimensions and the cross measurements are equal, your rectangular box will be square.

Answer 5

You are .75 of an inch off of square.  You need to think in fours.  If you are 6" over or under size you are 1.5" off on each corner.  Deducting that much MAY solve your issue OR adding 1.5" if you are exceeding the square.  It is hard to see it from this box on my monitor but try it on a piece of paper first.

Answer 6

Mark center points at the joints, and get your

diagonals EQUAL.

Measuring corners is too hard to do accurately.

(BTW, I get 42' 7.5")