Answer:
Step-by-step explanation:
The sum of the interior angles = 180 (n-2)
where n is the number of sides of the polygon.
1) if the sum of the interior angles of a polygon equals 1980,
180(n - 2) = 1980
180n - 360 = 1980
180n = 1980 + 360 = 2340
n = 2340/180 = 13
2) if n = 9, the number of degrees would be
180(n - 2) = 180(9 - 2)
= 180 × 7 = 1260 degrees
3) 180(n - 2) = 1620
n - 2 = 1620/180 = 9
n = 9 + 2 = 11
4) n = 18
The number of degrees would be
180(n - 2) = 180(18 - 2) = 2880 degrees.
5) n = 17
The number of degrees would be
180(n - 2) = 180(17 - 2) = 2700 degrees.
6) the sum of the interior angles of a quadrilateral is 360 degrees.