After languishing on the design wall for over a month, the Mediterranean Rose quilt has finally made it onto the longarm frame. I have high hopes for getting it quilted this week, though I need the design wall more!
This quilt has blocks set on point, which requires corner and side triangles to complete the square shape. So let's have a refresher course on measuring and cutting side and corner triangles for quilts with those on-point layouts, no matter if the finished quilt is square or rectangular.
In the picture below, the Side Triangles are in black (for this layout there are 2), and the Corner Triangles are in red (there are 4).
Side Triangles
The process below makes 4 (four) side triangles. Repeat the steps for more side triangles, or follow the Corner Triangle process to make just 2 (two).
To figure what size square to cut for Side Triangles, measure the short side of the quilt's side triangle area (in the blue oval), or use the finished block size of the quilt blocks. Personally, I like to measure, because fabric has a way of either growing or shrinking!
Multiply that measurement by 1.414, then add 1 1/4" (or 1.25). Round up to the nearest 1/8" (or add .125).
Side Triangle Formula:
(side measurement x 1.414) + 1.25; round up to nearest 1/8 (or add .125).
Example: (10" x 1.414) + 1.25 = 15.39. Rounded up, I'd cut the square at 15 1/2" (15.50).
The next step is to cut the square on both diagonals, yielding 4 side setting triangles. I love this because it creates the straight of grain on the outside edge for the quilt.
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straight of grain on outer edge |
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Makes 4 (four) side triangles |
Corner Triangles
The process below makes 2 (two). Repeat the steps to make a total of 4 (four) for all the corners.
To figure what size square to cut for the Corner Triangles, measure the long edge of the quilt top corner, as circled in blue above.
Multiply that measurement by .707 and add 7/8 (or .875), and round up to the nearest 1/8" (or add .125) for the size square to cut.
Corner Triangle formula:
(corner measurement x .707) + .875; round to the nearest 1/8 (or add .125).
This time, cut the square on one diagonal, making a half square triangle unit.
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straight of grain on outer edges of corners |
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Makes 2 (two) Corner Triangles |
And there you have it - the math to make any size triangle for an on-point quilt.
Enjoy!
Need more quilting tutorials? Check out the Tutorial page!