Mary's Triangle Calculator
by Deborah Jones (firstname.lastname@example.org)
From any set of instructions for a quilt block containing Mary's Triangles, begin
with the measurement for the small corner unit, referring to the following
You will make all other calculations for each set of two (2)Mary's Triangles
units based on this measurement. For the examples, we use a 4" finished
(4-1/2" raw) Mary's Triangle unit. In the examples, width = the short side
measure; length = the long side measure.
For each TWO Mary's Triangle units:
- Cut 2 small squares for corner units at the measure prescribed for your
- Cut 2 small rectangles that will form the small side traingles. Short side
(width) measures the same as unit in step 1. Long side (length) is that
measure plus 1 inch.
Example: Width = 2-1/2" + 1" = 3-1/2"
- Cut 1 large rectangle that will form the two large triangles, using the
Width = Measurement from step 1 multiplied by 2 minus 1/2-inch seam allowance.
Example: 2-1/2" X 2 - 1/2" = 4-1/2"
Length = Width computed above for this large rectangle plus 1"
Example: 4-1/2" + 1" = 5-1/2"
Therefore, cut one rectangle at 4-1/2" X 5-1/2".