The points (5,-4,2), (4,-3,1), (7,6,4) and (8,-7,5) are the vertices of a. a rectangle                  b.  a square                c. a parallelogram           d. none of these

Explanation

Let, `A(5,-4,2), B(4,-3,1),C (7,6,4) and D(8,-7,5)`


So, `AB=sqrt[(5-4)^2+(-4+3)^2+(2-1)^2]=sqrt(1+1+1)=sqrt3`


`BC=sqrt[(4-7)^2+(-3-6)^2+(1-4)^2]=sqrt(9+81+9)=sqrt(99)=3sqrt11`


`CD= sqrt[(7-8)^2+(6+7)^2+(4-5)^2]= sqrt(1+169+1)=sqrt(171)`


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