Nonagon side = 12

The of an nonagon is

The side of an nonagon is 12. Calculate perimeter, area

Calculate Perimeter:
P = 9 x side
P = 9 x 12
P = 108

Calculate Area:
A = 9/4s2cot(180°/9)
A = 9/4(12)2cot(20)
A = 9/4(144)cot(20)
A = 324 x 2.4
A = 806

Calculate Sum of the Interior Angles:
Interior Angle Sum = (sides - 2) x 180°
Interior Angle Sum = (9 - 2) x 180°
Interior Angle Sum = 7 x 180°
Interior Angle sum = 1260°

Calculate the number of diagonals of the polygon:
Diagonals =n(n - 3)
2

Diagonals =9(9 - 3)
2

Diagonals =9(6)
2

Diagonals =54
2

Diagonals = 27

Calculate the number of diagonals from one vertex:
1 vertex Diagonals = n - 3
1 vertex Diagonals = 9 - 3
1 vertex Diagonals = 6

Calculate the number of triangles that can be drawn from one vertex:
Triangles = N - 2
Triangles = 9 - 2
Triangles = 7