Question

The number of diagonals of an octagon is __how much and how
____

Answer 1

Answer:

these lines from two points contain 8 lines which are the side of the octagon so we have to subtract 8 from 28 to get the number of diagonals. Hence, the number of diagonals of the octagon is 20

Answer 2

Answer:

Octagon has 20 diagonals

Number of diagonals =n(n-3)/2

= 8*5/2

=20