Platinum moment -- need help please!
#1
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Join Date: Aug 2009
Location: Somewhere near the water in beautiful Michigan
Posts: 772
I have a center for a quilt that is on point and I want to put setting triangles on the sides to square it up. Good idea, right? Well ........ :oops:
I don't remember enough geometry for how to go about determining the sides of a triangle when I know the hypoteneuse. In other words, I know the diagonal for a half-square triangle, but I don't know the sides. :shock:
Can anyone help me? I need to get this done this week, please! :(
Thanks so much,
Platinum Odessa
:roll: :oops: :roll:
I don't remember enough geometry for how to go about determining the sides of a triangle when I know the hypoteneuse. In other words, I know the diagonal for a half-square triangle, but I don't know the sides. :shock:
Can anyone help me? I need to get this done this week, please! :(
Thanks so much,
Platinum Odessa
:roll: :oops: :roll:
#3
#4
Super Member
Join Date: Aug 2009
Location: The middle of an IL cornfield
Posts: 7,014
Try this......you just put in the info you know about your triangle and it figures out the rest. I asked my husband the math whiz and he said it is accurate. Goodness knows I wouldn't know for myself.
http://easycalculation.com/trigonome...gle-angles.php
http://easycalculation.com/trigonome...gle-angles.php
#5
I had to figure this out for myself yesterday. The way I did it was to measure from the center of my quilt to the corner, and that measurement was the width and height of my triangle. I measured it out and cut a square of my fabric (plus a half inch for error) and then cut from corner to corner to make 2 triangles. The triangles fit perfectly.
does that make sense?
does that make sense?
#7
#8
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Join Date: Aug 2009
Location: Somewhere near the water in beautiful Michigan
Posts: 772
Originally Posted by Lisa_wanna_b_quilter
Try this......you just put in the info you know about your triangle and it figures out the rest. I asked my husband the math whiz and he said it is accurate. Goodness knows I wouldn't know for myself.
http://easycalculation.com/trigonome...gle-angles.php
http://easycalculation.com/trigonome...gle-angles.php
My 10th grade Geometry teacher would be SOOOOOOOOOOo disappointed! Oh, well!
Thanks one and all for the help, though, I think I will be able to manage it tonight.
#9
Okay, Geometry teacher here, let's see what I can do:
On a 45-45-90 triangle (where one side is a right angle, and the legs are equal), the sides are x, x, and x*sqrt(2). So, if I know that one leg is 5, the other leg is 5, meaning the hyp is 5*sqrt(2) or about 7.07.
So if you know the LEG and want to find the HYPOTENUSE, multiply the leg by sqrt (2).
If you know the HYPOTENUSE, then DIVIDE by sqrt (2) to get the legs. Ex: If my hyp is 7, each leg is 7 / sqrt(2) or about 4.95 (and if you think about this, this makes sense since it's close to what we figured out in the above one).
What I do, is I find out about how long the legs are, and then add 1/2" for seam allowance. It's not exact, but I'd rather have too much then too little. I have a bit of trouble working the seam allowance into my calculations because you lose part of the point, so I just add a little extra.
Hope this helps. Let me know if you need more
On a 45-45-90 triangle (where one side is a right angle, and the legs are equal), the sides are x, x, and x*sqrt(2). So, if I know that one leg is 5, the other leg is 5, meaning the hyp is 5*sqrt(2) or about 7.07.
So if you know the LEG and want to find the HYPOTENUSE, multiply the leg by sqrt (2).
If you know the HYPOTENUSE, then DIVIDE by sqrt (2) to get the legs. Ex: If my hyp is 7, each leg is 7 / sqrt(2) or about 4.95 (and if you think about this, this makes sense since it's close to what we figured out in the above one).
What I do, is I find out about how long the legs are, and then add 1/2" for seam allowance. It's not exact, but I'd rather have too much then too little. I have a bit of trouble working the seam allowance into my calculations because you lose part of the point, so I just add a little extra.
Hope this helps. Let me know if you need more
#10
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Join Date: Aug 2009
Location: Somewhere near the water in beautiful Michigan
Posts: 772
Lucy, thank you! I tried to do it that way in the first place, but was not coming up with what I felt to be a credible answer. When I get home tonight I will make that attempt one more time and see how it all plays out.
You guys are truly awesome!
Odessa
You guys are truly awesome!
Odessa
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