The angles in that tool (tri-rec) are approximately
skinny right triangle: 63.4, 26.6, and 90 degrees
the isoceles triangle:63.43, 53.13, 63.43 degrees
I rounded the degrees so those numbers are not 100% accurate.
There are a lot more decimals than i listed.
There is a kaleidoscope or spider web ruler that is an isoceles triangle and the angles in that one are
67.5 , 45, and 67.5 degrees. The " companion" triangle for that is 67.5, 22.5, and 90 degrees.
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The angles in a half square triangle (and also a quarter square triangle) are 45, 45, and 90 degrees.
the equilateral triangle is 60, 60, and 60 degrees. The " companion" triangle to that is 30, 60, and 90 degrees.