Flag of Newfoundland and Labrador  — construction sheet
Own work. Geometry and dimensions based on the official specification sheet created in 1980 by the Flag's designer (Christopher Pratt).
Note that the original specification sheet is missing the angle of the two white diagonal lines.  They are assumed to be 30° from the horizonal thus forming part of an equilateral triangle.

See also Christopher_Pratt_2010_lecture_notes which shows an assortment of early sketches (including one with a labeled equilateral triangle).
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