Found this site this AM. Hope it helps those of us that are lost when it comes to figuring fabric needs for different shapes besides rectangles and squares:
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Square Rectangle Half-Square Triangle Half-Rectangle Triangle Quarter-Square Triangle (new!) Trapezoid (45°/135° corners) Parallelogram (45°/135° corners)Just mark the appropriate box and give the sizes needed and it does the work: ) I haven't tried it as of yet, as I said, I just found it. HTH
Butterfly