3. Verify that the points $O ( 0,0,0 ) , A ( 1,4,8 ) , B ( - 6,0,12 )$ and $C ( - 7 , - 4,4 )$ are coplanar. Calculate the area and perimeter of the quadrilateral $O A B C$ and classify it.
3. Verify that the points $O ( 0,0,0 ) , A ( 1,4,8 ) , B ( - 6,0,12 )$ and $C ( - 7 , - 4,4 )$ are coplanar. Calculate the area and perimeter of the quadrilateral $O A B C$ and classify it.\\