Answer:
3 non-congruent triangles
Step-by-step explanation:
Assume, side of cube is 1 unit.
24 triangles, faces of cube and side lengths = 1,1,√2
24 triangles, by 2 diagonal and one side and length = 1,√2
,√23
8 triangles, using bases of tetrahedrons of the cube and side lengths = √2
,√2
,√2
Therefore, 3 non-congruent triangles. are formed.