The angle between the diagonals of the parallelogram formed by the points (1,2,3),(-1,-2,-1),(2,3,2),(4,7,6) is

Find the coordinates of the point where the diagonals of the parallelogram formed by joining the points (-2,-1),(1,0),(4,3) and (1,2) meet.

If theta is the angle between the diagonals of a parallelogram ABCD whose vertices are A(0,2),B(2,-1),C(4,0) and D(2,3) Show that tan theta=2

Show that the points A(1,2,3),B(-1,-2,-1)C(2,3,2),D(4,7,6) are the vertices of a parallelogram.

The distance between the circumcentre and the orthocentre of the triangle formed by the points (2,1,5)(3,2,3)(4,0,4) is

The angle between the lines passing through the points (8, 2, 0), (4, 6, -7) and (-3, 1, 2), (-9, -2, 4) is

Find angle between the lines formed by joining (2,2,1) with (3,1,4) and (7,2,2)

The extremities of a diagonal of a parallelogram are the points (3, -4) and (-6, 5) . If third vertiex is (-2, 1) then the coordinates of the fourth vertex are