Show that the four points (1, 0), (2,-7), (8, 1) and (9,- 6) are concyclic.

Show that the points A(1, 0), B(2, -7), C(8, 1) and D(9,-6) all lie on the same circle. Find the equation of this circle, its centre and radius.

Prove that the points (1,- 6), (5, 2), (7, 0) and (- 1,-4) are concyclic. Find the radius of the circle.

Show that the four points S(0,-1,0), B(2,1,-1), C(1,1,1) and D(3,3,0) are coplanar. Find the equation of the plane containing them.

Show that the points (1,0,1),(1,1,0),(0,1,1) and (0,0,2) are coplanar.

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

Show that the points A(1,2,7), B(2,6,3) and C(3,10,-1) are collinear.

Show that the points A(1,3,2),B(-2,0,1) and C(4,6,3) are collinear.

Show that the points A (1, - 2, - 8), B (5, 0,- 2) and C (11, 3, 7) are collinear, and find the ratio in which B divides AC.

Show that the points (0,-1,-1) , (-4,4,4) , (4,5,1) and (3,9,4) are coplanar.