For the following two (02) items:
Let A(1, - 1, 0) B(- 2, 1, 8) and C(- 1, 2, 7) are three consecutive vertices of a parallelogram ABCD.

What is the fourth vertex D?

For the following two (02) items:
Let A(1, - 1, 0) B(- 2, 1, 8) and C(- 1, 2, 7) are three consecutive vertices of a parallelogram ABCD.

If angle BCD is $\theta $ then what is $ cos^2 \theta$ equal to?

For different values of m, the equation 4y=mx-m+ 2 represents

The equation of the locus of a point equidistant from the points (a, b) and (c, d) is (a - c)  x + (b - d)  y + k = 0 What is the value of k?