Correct Answer - Option 3 : 54
Concept:
Number of diagonals on an n sided polygon = \(\frac{n(n-3)}{2}\)
Calculation:
Given that,
n= 12
By using the above formula,
⇒ Number of diagonal = \(\frac{12(12-3)}{2}\) = 54
∴ The number of diagonal is 51
The number of ways to select r things out of n things is given by nCr
\(\rm ^nC_r=\frac{n!}{(n-r)!\times(r)!}=\frac{n\times(n-1)\times....(n-r+1)}{r!}\)
