Question

O número de diagonais de um dodecágono convexo é:

Answer 1

Resposta:

O dodecágono possui 54 diagonais.

Answer 2

$\Large\displaystyle\begin{gathered} \tt d=\frac{n\cdot(n-3)}{2}\end{gathered}$

$\Large\displaystyle\begin{gathered} \tt d=\frac{12\cdot(12-3)}{2}\end{gathered}$

$\Large\displaystyle\begin{gathered} \tt d=\frac{12\cdot9}{2}\end{gathered}$

$\Large\displaystyle\begin{gathered} \tt d=\frac{108}{2}\end{gathered}$

$\Large\displaystyle\text{ \begin{gathered} \boxed{\red{\tt d=54}} \end{gathered} }$