Question

calcule o numeros de diagonais do enegono 9 vertices ?????

Answer 1

$d= \frac{n(n-3)}{2} = \frac{9(9-3)}{2} = \frac{9(6)}{2} = \frac{54}{2} =27 \\ \\ O~~ene\'agono~~tem~~27~~diagonais$