20
20 diagonals in Octagan. For n-sided polygon, no of diagonals = (n choose 2 ) - n = 8C2 - 8 = 28 - 8 = 20
20.
20 sides 1/2*(202-60) = 170 diagonals
A polygon that has 104 diagonals will have 16 sides
A 20 sided polygon has 170 diagonals
There are 170 diagonals
decagon
An octagon has 20 diagonals
It has 20 diagonals
A polygon with n sides had n*(n-3)/2 diagonals. So a 20 sided polygon would have 20*17/3 = 170
It is 18 diagonals
0.5*(202-60) = 170 diagonals
It has 170 diagonals by using the diagonal formula
170
20
20 diagonals in Octagan. For n-sided polygon, no of diagonals = (n choose 2 ) - n = 8C2 - 8 = 28 - 8 = 20