SOLUTION: What is the sum the interior angles of a 13-gon? What is the sum the interior angles of a 20-gon? What is the sum the interior angles of a 18-gon?

Algebra ->  Polygons -> SOLUTION: What is the sum the interior angles of a 13-gon? What is the sum the interior angles of a 20-gon? What is the sum the interior angles of a 18-gon?      Log On


   

Question 107979: What is the sum the interior angles of a 13-gon?
What is the sum the interior angles of a 20-gon?
What is the sum the interior angles of a 18-gon?
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!


The sum of interior angle ( Sum-of-interior-angles-n-gon) of n-gon is:
Sum-of-interior-angles-n-gon+=+%28n-2%29180
If we have a 13-gon, n=13
Then
Sum-of-interior-angles-n-gon+=+%2813-2%29180
Sum-of-interior-angles-n-gon+=+%2811%29180
Sum-of-interior-angles-n-gon+=+%2811%29180
Sum-of-interior-angles-n-gon+=+1980

If we have 20-gon, n=20
Sum-of-interior-angles-n-gon+=+%2820-2%29180
Sum-of-interior-angles-n-gon+=+%2818%29180
Sum-of-interior-angles-n-gon+=+3240

If we have 18-gon, n=18
Sum-of-interior-angles-n-gon+=+%2818-2%29180
Sum-of-interior-angles-n-gon+=+%2816%29180
Sum-of-interior-angles-n-gon+=+2880