Triangles in the two dimensions
Plane Trigonometry
Triangles extracted from the surface of a sphere
Spherical Trigonometry
Has a right angle
Right Triangle
Triangle that does not have a right angle
Oblique Triangle
can be a right triangle or an oblique triangle
Isosceles
Pythagorean Theorem
a²+b²=c²
5-4-3
Egyptian Triangle
45 45 90
Isosceles right triangle