Question

Formula to find the number of diagonals when side is given

Answer 1

Answer:n(n-3)/2

Step-by-step explanation:

Here n is the number of sides given.

Hope it helps you...

Answer 2

Answer:n(n-3)/2

Step-by-step explanation:

I will apply some permutation and combination here

For daigonals we have to chose any two vertices of the polygon except for the sides of polygon itself

Number of ways of choosing any 2 vertices of a polygon of n sides =nC2=n(n-1)/2

In this we have also included the sides thus excluding the sides we get

=n(n-1)/2 -n

=n(n-1-2)/2=n(n-3)/2...answer