Question

Calcular o número de diagonais de um duedecágono lembrando que:
$d \ = \ \: n \times \ \: ({n} - {3}) \\ 2$
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Answer 1

$\small\boxed{\begin{array}{l}\sf calcular~o~n\acute umero~de~diagonais~do~dodec\acute agono~regular\\\sf lembrando~que~ d=\dfrac{n\cdot(n-3)}{2}\end{array}}$

$\boxed{\begin{array}{l}\underline{\rm soluc_{\!\!,}\tilde ao\! :}\\\sf dodec\acute agono\longrightarrow 12~lados\\\sf n=12\\\sf d=\dfrac{\diagdown\!\!\!\!\!\!12^6\cdot(12-3)}{\backslash\!\!\!2}\\\sf d=6\cdot9\\\sf d=54\end{array}}$