62
I'm pretty sure it's 65
A tridecagon is a 13-sided figure.
Tridecagon
tridecagon
thirteenagon
13
They have: 0.5*(132-(3*13)) = 65 diagonals
If you mean "How many diagonals can be drawn from one vertex of a figure with 16 sides", the formula is n-3, where "n" being the number of sides of the figure. So 16-3 = 13 diagonals that can be drawn from one vertex.
78
13
Using the formula 0.5(n^2 -3n) whereas n is number of sides, altogether there are 104 diagonals in a 16 sided polygon