Question

Ajuda ai galera, por favor, Qual poligono regular com exatamente 27 diagonais? (monte a conta)

Answer 1

$D=\dfrac{n(n-3)}{2}\\\\27=\dfrac{n(n-3)}{2}\\\\54=n^2-3n\\\\n^2-3n-54=0\\\\(n+6)(n-9)=0\\\\n=-6\ \text{ou}\ n=9$

No caso um eneagono