High one vector addition operation In the triangle ABC, AB + BC = AC In quadrilateral ABCD, AB + BC + CD = AC + CD = ad In Pentagon ABCDE, AB + BC + CD + de = AC + CD + de = AD + de = AE What are the general rules?

High one vector addition operation In the triangle ABC, AB + BC = AC In quadrilateral ABCD, AB + BC + CD = AC + CD = ad In Pentagon ABCDE, AB + BC + CD + de = AC + CD + de = AD + de = AE What are the general rules?

N-sided a1a2a3a4 An Zhong
A1A2++A2A3+A3A4+A4A5+… +A(n-1)An=A1A3+A3A5+… +A(n-2)An=A1An