An octagon has 8 sides and 20 diagonals so the question doesn't make sense
It has 0.5*(35^2 -3*35) = 560 diagonals
35 diagonals
35
It has 10 sides because using the formula 0.5*(102-30) = 35 diagonals
A 35-gon has 560 diagonals 0.5*(352-3*35) = 560
octagon
There are 560 diagonals by using the diagonal formula
It has 0.5*(35^2 -3*35) = 560 diagonals
There are 35 diagonals in a 10 sided decagon
It has 35 diagonals
35 diagonals
(35*(35-3))/2 (35*32)/2 1120/2 560 diagonals
35.
35
35
35 diagonals
The number of diagonals is n(n-1)/2 - n substitute n=35 35(34)/2 - 35 = 560