If you mark 6 points on a circle how many quadrilaterals have 4 of th points as vertices

Question

15,10,12,or 8

Answer 1

If we call the points A, B, C, D, E and F, the quadrilaterals will be:

ABCD, ABCE, ABCF, ABDE, ABDF, ABEF, ACDE, ACDF, ACEF, ADEF, BCDE, BCDF, BCEF, BDEF, CDEF.

That makes 15 quadrilaterals. It's the same as how many ways there are of combining 4 objects out of 6 different objects, or combining 2 objects out of 6 different objects.

Answer 2

The answer 8