How many diagonals can be drawn from a vertex of an n-gon?

Answer 1

An n-gon has n(n-3)/2 total diagonals.

You can draw n-3 diagonals from each vertex ( n>3)

( A triangle doesn't really have a diagonal)

An alternative way of seeing this: from any vertex, you can draw a diagonal to any other vertex except itself and the immediate neighbour on either side (the latter would be sides of the n-gon). This gives n-3 diagonals.