For the Points $A ( 1 , - 2 , - 1 ) , B ( 2 , - 7,4 ) , C ( 1 , - 6 , - 5 ) , D ( 2 , - 11,0 )$

Essay

For the points $A ( 1 , - 2 , - 1 ) , B ( 2 , - 7,4 ) , C ( 1 , - 6 , - 5 ) , D ( 2 , - 11,0 )$ :
a. Verify that the points are vertices of a parallelogram. Show all work.
b. Find the area of the parallelogram. Show all work.
c. Determine whether the parallelogram is a rectangle.