Unlimited - you need one 90-degree angle, and the other two can be anything that add up to 90!
Right-Angle triangles
4 right triangles
All right-angles triangles. That is triangles that contain one angle at 90 degrees.
depends on what size triangles and what kind of triangles?
Right triangles - those with a 90-degree angle.
right triangle ( triangles with a right angle)
A rhombus can be split into 2 isosceles triangles or divided into 4 right angle triangles
6
Two of them
Many different types, but mostly equilateral triangles.
Any right-angled triangle
There are the equilateral, isoscoles, scalene, acute & obtuse. See the related link below: