The angles used in the Tri-Recs tools are:
90, and approximately 63.435, and 26.565 degrees for the skinny triangle,
and
approximately 63.435, 63.435, and 53.130 degrees for the "center' triangle.
If one does not have one of the Tri-Recs types of rulers, it is quite easy to draft one's own template for the unit.
Post #13 gives an example of what one would look like.