How many interior diagonals does a regular nine-sided polygon have? (An $\emph{interior diagonal }$ is a segment connecting two vertices which do not have an edge between them.)

Paresh Mar 25, 2020

#1**+2 **

Equation:

# of diagnols+9=(9×8)/(2×1)=36.

Therefore, number of diagonals=36–9=27.

Hope this helped!

CalTheGreat Mar 25, 2020