How was korea influenced by china and japan?

1) Chosun Dynasty: Koreans adopted confuscious from China
2) Korean language: adopted from Chinese 1000 years ago,and began to develop its own language in 1960s. All Korean historic documents were written in Chinese language systems, and it becomes sad that young Koreans can not read and understand its own past.
3) Koreans are close to ethnic of Manchuria ( which is part of Chinese ethics)

Use the formula: (n-2)×180, where n is the number of sides(18-2)×180= 28800, now this is the full exterior angle of 18-gon so you divide it by 18.28800÷18=160