Question

Tick (✓) the correct answer:
How many diagonals are there in a hexagon?
(a) 6
(b) 8
(c) 9
(d) 10

Answer 1

(c) 9
Number of diagonals in an n-sided polygon = $\frac{n\left(n-3\right)}{2}$
For a hexagon:

$$\begin{gathered} n=6 \\ \therefore \frac{n\left(n-3\right)}{2}=\frac{6\left(6-3\right)}{2} \\ =\frac{18}{2}=9 \end{gathered}$$