Donna left a great comment on the last blog entry.
“If I want to sew a HST to a side of a square, and I know the size of the side of the square (say, 2″), and I know that the diagonal of the HST has to be 2″ (duh!), what is the finished size of the HST going to be? Is there a formula for that?”
This is a great question. Yes, there is a formula, Donna.
We either multiply or divide, depending on which measurement we know.
The “magic number” is 1.414.
Yes, really. 1.414. I apologize.
In Donna’s example, the triangle would be 1.414 inches (finished), and it is available in an Inklingo shape collection.
Let me explain.
1.414 was discovered thousands of years ago by Pythagoras (left), and re-discovered by Monkey (right) when I was writing The Inklingo Handbook. LOL Luckily, someone had invented a calculator in the meantime.
Inklingo quilters only need a passing familiarity with Pythagoras (born about 570 BC), his theorems, hypotenuses, and square roots.
Just remember 1.414. That’s enough.
- If you know the number should be bigger than the one you know, multiply.
- If you know the number should be smaller than the one you know, divide.
If you know that B is 3 inches (finished size),
to get A, we divide by 1.414. A = 2.12
If you know that A is 3 inches (finished size),
to get B, we multiply by 1.414. B = 4.24
In Donna’s example, if we know B is 2 inches, we divide by 1.414, and A is 1.414. (That is spooky, until you realize that the square root of 2 is 1.414. Getting into deep water here. Quilters don’t need to know about square roots.)
When your calculator gives you the finished size, you can check to see if it is available by going to the Inklingo Index of Shapes (under the Support tab on inklingo.com).
2.12 inch HST? YES! Available! So are 1.41 inch HST. Isn’t that cool? Also 4.24 and 2.83 and others. Designs like Storm At Sea are chock full of weird measurements like this, but you don’t have to fear them anymore!
If anyone had told me 40 years ago how useful geometry would be to me now, I would not have believed it. Since Inklingo, Pythagoras and I are BFF.
NO MATH !
Hooray! Inklingo does all the work for you. You just print precise shapes on fabric with your ordinary Inkjet printer. No measuring, no fuss. Perfect shapes. Even Storm At Sea becomes easy. (Get the design book—$10 or free!)
In many cases, quilters start with the finished size of the whole block, and work backwards to get the finished size of the triangles and the square.
For example, if you know you want the block to be 4 inches (finished),
A = 2
A x 1.414 = B = 2.83
When we look in the Inklingo Index of Shapes, we see that the squares and HST are available in one of the shape collections. Life is good.
INKLINGO INDEX OF SHAPES
There are several odd-looking sizes in the Index of Shapes. Now you know why.
- Snowball block Video
- Triangle Tips PDF
- The Inklingo Handbook, pages 114 and 115 discuss the magic number 1.414
Whew! Thank you, Donna, for a great question!
Linda & Monkey
PS Don’t forget to leave a comment HERE to have a chance to win a $25 Gift Certificate on Mother’s Day!
New to Inklingo? Order and download free shapes and start sewing in the next few minutes. Quick Start (Always FREE.) There are triangles, diamonds, and squares in the free collection—great for dozens of different blocks.