Simple math problem
#1
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Location: Mason, Ohio
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Simple math problem
I finished a machine embroidered design on linen and want to make it into a pillow. The directions I have for the envelope pillow called for a piece of fabric 19x15. I wanted a smaller pillow and wanted to reduce the long side to 15. I got stuck trying to figure this out. We were at dinner that evening,so I thought, I'll ask the high school/college ages servers to figure it out for me. It became pretty funny as they would all start the calculation and say, "I can't figure it out." One came up with the answer of 19. I know how she did it, but it didn't make sense to me that if I was reducing it, how could it come on larger. I decided to let it rest, and if I couldn't figure it out, I'd ask my nephew (a computer guru). Well, the light bulb went on. I figured it out, and didn't embarrass myself to my nephew. Just for fun, can you figure it out?
Last edited by eimay; 02-17-2018 at 01:12 PM. Reason: Inclorrect word
#4
If you want the same ratio in the pillow's size, then you also have to take the seams into account, just like you do when re-sizing a quilt block. With quilting you would use 1/4" seams, but with a pillow I would think you would take bigger seams. Do you want the pillow's long finished side to be 15, or do you want the unfinished side to be 15? How big are your seams? There's not enough information here to give you an answer, but if you're not concerned about the seams then bearisgray has the right answer. (Although I don't know what she means by those last two lines...)
#5
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Join Date: Aug 2010
Location: PA
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I'm not sure if this is right but here goes......You said you want a smaller pillow & wanted to "reduce" the long side. The fabric is 19 inches x 15 inches.
Keeping the same ratio, if reducing/cutting the fabric:
19-15=4 19-4=15. Add 1/2 inch seams to each side = fabric would be 16 inches long
15-4=11. Add 1/2 inch seams to each side = 12 inches wide.
So you would cut the fabric 16 inches long x 12 inches wide. After sewing the pillow would be 15 inches long x 11 inches wide.
Now if you are only reducing one side, since you stated you wanted it reduced in length. Then all you do is turn it around so you have 15 inches long x 19 wide, instead of 19 inches long x 15 inches wide. No cutting.
Keeping the same ratio, if reducing/cutting the fabric:
19-15=4 19-4=15. Add 1/2 inch seams to each side = fabric would be 16 inches long
15-4=11. Add 1/2 inch seams to each side = 12 inches wide.
So you would cut the fabric 16 inches long x 12 inches wide. After sewing the pillow would be 15 inches long x 11 inches wide.
Now if you are only reducing one side, since you stated you wanted it reduced in length. Then all you do is turn it around so you have 15 inches long x 19 wide, instead of 19 inches long x 15 inches wide. No cutting.
#6
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Feather3, I like the way you did this, but you are not keeping the ratios the same by subtracting 4 from each side. When you subtract 4 from 19, you are reducing the 19" side by 21%. To keep the ratios the same, you need to reduce the 15" side by 21% also, which means subtracting about 3.15 (.21 x 15") from that side instead of 4.
#7
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Feather3, I like the way you did this, but you are not keeping the ratios the same by subtracting 4 from each side. When you subtract 4 from 19, you are reducing the 19" side by 21%. To keep the ratios the same, you need to reduce the 15" side by 21% also, which means subtracting about 3.15 (.21 x 15") from that side instead of 4.
#8
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Join Date: Aug 2010
Location: PA
Posts: 680
I went back & read this again....."I have for the envelope pillow called for a piece of fabric 19x15. I wanted a smaller pillow and wanted to reduce the long side to 15. "
It doesn't say ....reduce the entire pillow in size....just the long side.
So if the fabric is 19 inches long x 15 inches wide & she wants to reduce the long side to 15 inches (assuming before sewing) then cut off 4 inches from the long side. End result would be 15 inches x 15 inches cut fabric. Take off for seams & the pillow would measure 14 inches x 14 inches finished, using 1/2 inch seams.
It doesn't say ....reduce the entire pillow in size....just the long side.
So if the fabric is 19 inches long x 15 inches wide & she wants to reduce the long side to 15 inches (assuming before sewing) then cut off 4 inches from the long side. End result would be 15 inches x 15 inches cut fabric. Take off for seams & the pillow would measure 14 inches x 14 inches finished, using 1/2 inch seams.
#9
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Join Date: May 2017
Location: Sunny Florida
Posts: 4,434
There are other factors to consider before giving cut measurements. We need more information on your project.
What is the finished size of the embroidery piece for the pillow?
Add one inch for seams and cut the backing fabric. For pillows you want to seam with 1/2 inch seams.
Are you adding a zipper? Hidden? You need to add for the zipper placket also.
What is the finished size of the embroidery piece for the pillow?
Add one inch for seams and cut the backing fabric. For pillows you want to seam with 1/2 inch seams.
Are you adding a zipper? Hidden? You need to add for the zipper placket also.
#10
These are the assumptions I am using: the dimensions give above are raw not finished dimensions; I'm using 1/2" seam allowances; she is looking for the size of material she needs rather than the finished pillow size.
Given these assumptions I first subtract my seam allowances because they will remain constant regardless of the size of the pillow therefore I'm looking at an initial size of fabric of 18x14. I will also need to subtract the seam allowances from the smaller pieces so I am looking at a piece that will be 14x?. I need to solve for the unknown.
Ratio analysis is done by comparing 18:14 = 14:x or another way of putting it is 18/14 = 14/x. Solving this equation I get 18x = 14(14) or 18x = 196 or x = 196/18 or x = 10.888 which I would round to 11.
Now I need to add back in my seam allowances so I end up with a piece of fabric that would be 15x12 to keep the same proportions as the original piece of fabric. In other words 19x15 is proportionally equal to 15x12
Given these assumptions I first subtract my seam allowances because they will remain constant regardless of the size of the pillow therefore I'm looking at an initial size of fabric of 18x14. I will also need to subtract the seam allowances from the smaller pieces so I am looking at a piece that will be 14x?. I need to solve for the unknown.
Ratio analysis is done by comparing 18:14 = 14:x or another way of putting it is 18/14 = 14/x. Solving this equation I get 18x = 14(14) or 18x = 196 or x = 196/18 or x = 10.888 which I would round to 11.
Now I need to add back in my seam allowances so I end up with a piece of fabric that would be 15x12 to keep the same proportions as the original piece of fabric. In other words 19x15 is proportionally equal to 15x12
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