What is the number of diagonals of an $n$-sided polygon?

Question

Accepted Answer

Total line segments joining $n$ vertices is $^{n}C{2}$. Subtracting the $n$ sides of the polygon, the number of diagonals is $^{n}C{2} - n = \frac{n(n-1)}{2} - n = \frac{n(n-3)}{2}$. Thus, option D is correct.

Permutations and Combinations

❓ Sibling Questions in this Chapter