Let ` vec a , vec b , vec c , vec d` be the position vectors of the four distinct points `A , B , C , Ddot` If ` vec b- vec a= vec a- vec d ,` then show that `A B C D` is parallelogram.

Explanation

Given a,b,c,d

are the position vectors of the four distinct points `A,B,C,D`


So `ABCD` will be a quadrilateral


And also we have


`b−a=c−d`

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