How many non-congruent triangles have vertices at three of the eight points in the array shown below?
Answer Choices
A. 5
B. 6
C. 7
D. 8
E. 9
How many non-congruent triangles have vertices at three of the eight points in the array shown below?
Answer Choices
A. 5
B. 6
C. 7
D. 8
E. 9