How many diagonals does a nine sided polygon?

Answer 1

A 9-sided polygon, is named 'Nonagon'.

The number of diagonals are '9'

From any one node, to the centre of the opposite side.

Since there are 9 nodes and 9 lines, then there will be 9 diagonals.

Answer 2

For an n-sided polygon, the number of diagonals is 1+2+3+....+(n-4)+2(n-3).

For a nine-sided polygon, there are 1+2+3+4+5+2(6)=27 diagonals.