Setting triangles calculator
CalculatorWhen typing decimals, use . (point) instead of , (comma) or the applet will not work.
Java applet courtesy of Ellinor Førde. If you found it useful, please
Your results will most often contain numbers with decimals. For those of you who work with inches, you will want to convert the decimals to fractions.
Use the table below. If you do not find the exact decimals in the table, use the closest one above your number - then your triangles will not be too small. (Too big - you can always trim afterwards).
Adding Seam Allowance
The calculations above are for the finished size of the half square triangles.
Before you cut the square, you must add to the measurements of the square (which was calculated above) so that you allow for seam allowance for both the resulting triangles.
How much to add depends on what seam allowance you use when sewing.
If your seam allowance is 1/4'', then you must add 7/8'' to your measurements before you cut the square.
When using metric measurements:
Add 1,7 cm if you use a seam allowance of 0,5 cm
Add 2,56 cm if you use a seam allowance of 0,75 cm
More than four rounds of triangles in the block?
Look at the results you got in your calculation above. Can you see a "pattern" in the numbers?
Note that the square for cutting triangles no 2 are the same size you started out with (center square), and then triangles 4 are the double of no 2.
Likewise, triangles no 3 are twice the size of triangles no 1. Then we may expect that a 5th row of triangles will be double the size of no 3. The 6th row will be double the size of no 4.... ...and so on.
(Results with decimals will not always show the exact double because some decimals have to be rounded off during calculation)
Setting a block on point
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