Question

formula for taking out the diagonal of a polygon

Answer 1

Number of diagonals of a polygon of side 'n' is given by:
$\frac{((n) \times (n - 3))}{2}$
For example,
Consider a 4 sided polygon (square)
Here n=4
Substituting n=4 in the formula ,
we get number of diagonals as 2

Hope this helps ☺️