How many triangles can be formed by joining the vertices of an octagon? Choose the correct option.
A) 50  B) 56  C) 23  D) 12  E) 89
Here n = 8   Hence, the number of triangles that can be formed by joining the vertices of an octagon   =n(n−1)(n−2)/6=8(8−1)(8−2)/6=8.7.6/6=56   Anwer is 56
<result>B</result>
How many triangles can be formed by joining the vertices of an octagon?