Try this option:
1. Rule for the sum of interior angles is: S=180°(n-2), where n - numbers of sides of n-gon.
2. using the formula shown above:
7 - 180*11=1980
8 - 180*16=2880
9 - 180*30=5400°
10 - 180*33=5940
11 - 180*5=900
12 - 180*24=4320
13 - 180*8=1440°
14 - 180*21=3780
