A ball is thrown upwards from the plane surface of the ground. Suppose the plane surface from which the ball is thrown also consists of the points \(A(1,0,2)\), \(B(3,-1,1)\) and \(C(1,2,1)\) on it. The highest point the ball reaches is \(D(2,3,1)\) as shown in the figure. [Figure: a ball at D (2, 3, 1) above a plane surface; line segments join D to the points A (1, 0, 2), B (3, -1, 1) and C (1, 2, 1) lying on the plane.] Using this information answer the questions.