a polygon of 100 sides has all possible drawn from a chosen vertex to the others. how many triangles are formed

98

Step-by-step explanation:

for a 4 sided polygon you can only draw one diagonal from one vertex so it forms 2 triangles.

For 5 sides you get 3 triangles

For 6 sides - 4

For 7 sides - 5

For 8 sides - 6

Looks like we get 2 less triangles than the number of sides in the polygon

Answer for 100 sides is 98 triangles.