geometry polygon nonagon and pentagon questions

Question

Can someone help me understand the following question and give a good explination:

What is the size of each interior angle of twenty-sided regular polygon and how is it calculated

What is the sum of the interior angles of a nonagon?

What is the sum of exterior angle of a polygon..?

What is the size of the exterior angle of a regular pentagon.

Answer 1

What is the size of each interior angle of twenty-sided regular polygon and how is it calculated 180(20-2) / 20 = 162 degrees.

What is the sum of the interior angles of a nonagon? 180(9-2) = 1260 degrees.

What is the sum of exterior angle of a polygon..? 360 degrees.

What is the size of the exterior angle of a regular pentagon. 360/5 = 72 degrees.

Answer 2

I=(N-2)180 MINUS SUM OF GIVEN EXTERIOR ANGLES

Answer 3

1. 162 degress. Formula- 180*(n-2)/n [n=number of sides]

2. 1260 degress Formula- 180*(n-2)  [n=number of sides]

3. 360 degrees

4. 180-108= 72 degress. [108 degress= the interior angle of a pentagon]