suppose a cube is given. How many non-congruent triangles can be formed by connecting 3 of the vertices of the cube?

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.

answer: 180

step-by-step explanation:

12-2=10

20-2=18

18x10=180