Why is the right angle triangle the foundation of trigonometry instead of any other type?
Because the hypotenuse of every right triangle can be also seen as the radius of a circle, with one of the non-right angles also serving as a refrence angle at the origin of the XY graph. The origin becomes, then, the circle’s center. In doing this, the 2 legs sit horizontally (x-axis) and vertically (y-axis), the point on the circle has an (x,y) position also. The right angle, resultant, is sitting on the x-axis. No other shape exists at basic trigonometry understanding that can utilized as a foundation – at least at the level where Trig is introduced to student-based learning. Unfortunately for the above previous replies, they DO NOT EXPLAIN YOUR ANSWER AS YOU ASKED IT. The pythagorean theorem is understood to relate sides of a triangle to themselves, whereas the relationship that sides of a triangle have with angles isn’t known until you you can establish where definition for sine, cosine, and tangent come from. The combining of coordinate plane (x,y) and right triangles occurs, joi
