With 180*(N-2)+x=2000, it is easy to know 0.
180*(N-2)=2000-x, so 2000- 180.
10. 1 1 & lt; n-2 & lt; 1 1. 1 1
Because n is a positive integer, N-2= 1 1, N= 13.
180*( 13-2)+x=2000,x=20。
The outer angle is 20.