Question

2) Calcular o número de diagonais do actógono

Answer 1

octógono ⇒ n =8

$d= \frac{n(n-3)}{2} \\ \\ d= \frac{8(8-3)}{2} \\ \\ d= \frac{8.(5)}{2} \\ \\ d= \frac{40}{2} \\ \\ d=20 \\ \\ logo~~tem~~20~~diagonais$