Sunday, April 29, 2007

How many seams

I had an initial theory about how many seams it would take to join 756 triangles together into a single quilt top, but when I did the math it turned out I was wrong.

Any guesses?


tAnYeTTa April 29, 2007 9:47 PM  

i have no idea but, i'm sure it will turn out really cool. i'm here by way of crazy hip blog mamas. wanted to say hello. stop by my blog when you can :)

Sandy April 29, 2007 9:53 PM  


theotherbear April 29, 2007 10:54 PM  

umm about a billion?

However many it is, I bet it feels like at least double that :)

Erin April 30, 2007 10:32 AM  

*sigh* Ok. I wasn't going to do this, but now I'm all curious.

So there are 12 triangles and 12 seams per block. And there are 9 rows by 7 columns of blocks, which is 54 blocks. 12 x 54 = 648 seams per block, plus the seams needed to attach the blocks to each other. 6 seams are needed to create one row of blocks, multiplied by 8 (one fewer than the number of rows because one end isn't going to be seamed right away), gives us 48 seams to make the rows, for a grand total of 31,104. Am I close? :)

Jennifer April 30, 2007 4:48 PM  

And the answer is:

It actually takes 755 seams to join 756 triangles. Isn't that interesting?

Sandy, you got almost the exact same answer as me, no surprise there! Our calculations differ by six seams - I wonder if you calculated the right number of blocks, but then missed a row or column when joining the blocks together?

Erin, you were totally on the right track as far as how to figure it out, but I think your calculator needs a new battery ;)

Also, you got the number of seams per block, then multiplied it by the number of blocks in the quilt, which is right, but then you multiplied it a second time, which got you off by a factor of, well whatever that's a factor of.

Sandy April 30, 2007 7:41 PM  

There are only 11 seams per block, right? 11 x 63=693. 6 seams per row x 9=54. Now up to 747. 8 seams to put rows together=755! Aha! Wonder where I (we) missed the other 6? It was around midnight when I was doing my figuring the first time, how about you, Jen? Good thing we don't have to have the right answer to make a beautiful quilt ;)

Anonymous April 30, 2007 7:58 PM  


Dad May 01, 2007 7:26 PM  

I wasn't going to weigh in on this, but I must.

12 seams per block
63 blocks
756 seams

Plus 14 (long) seams to sew the blocks together
results in
770 seams

Seems right to me. Where did I go wrong? And which seam did you leave out to get the 755 seams?

Jennifer May 01, 2007 8:14 PM  

The biggest difference is that, as Sandy notes, there are only 11 seams per block.

The corner pieces give us 4 seams right off the bat.

For the rest of it, the eight central triangles are joined into pairs: 4 seams.

Then the pairs are joined into halves: 2 seams.

Then the halves are joined together: 1 final seam (not two).

So that's 11 * 63 = 693

Then the blocks are joined into rows. It takes 6 seams to create each row (of 7 blocks). There are 9 such rows, so it takes for 54 seams to create the rows.

Then there are a final 8 long seams to join the rows into a top.

693 + 54 + 8 = 755

Incidentally, the result is the same if I join the blocks into nine columns of seven, then sew the columns together: 8 seams times 7 columns, plus six seams to join them.

juliloquy May 02, 2007 6:20 AM  

And now even more in need of a nap. In the immortal words of Barbie, "math is hard!"

Anonymous May 02, 2007 5:35 PM  


Dad May 02, 2007 5:39 PM  

No, Anonymous (I mean, anonymous) did NOT say Tio! *I* said Tio!
(Finger must have hit a "send" key about which I'm ignorant.)

I was counting 12 seams per block based upon each inner triangle having all three sides seamed. I did not notice that the longer seams on each triangle would go all the way across and connect two triangles.

Oh well (in English) UNCLE! I give up! Enough! (I'm with Julie.)

Anonymous May 02, 2007 5:52 PM  

This is a test. This is only a test. I'm trying to figure out why, occasionally, a comment I'm writing posts before I'm finished with it. Jennifer has a theory, and I'm testing it out. Here. Now.

Dad May 02, 2007 5:56 PM  

Huh. The theory failed. So I started to try other keystrokes, and INADVERTENTLY posted AGAIN. BEFORE I typed in "Dad."

The space bar has something to do with it.Let me fuss with it some more.


I give up. I can't get it to post by any other means than selecting "Publish Your Comment."


sandy May 02, 2007 6:53 PM  

I think the shift key has something to do with it, Dad.

Dad May 02, 2007 7:08 PM  

I guess I need to learn how to be shiftless, Sandy.

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