...1, 2), R = (-2, -1, 1). Find the area of the triangle PQR...
Let A = (3, -2, -5) \\ B = (-1, -6, -9) \\ C = (-6, -5, -8) \\ D = (-2, -1, -4) Find the area of the parallelogram determined by these four points, the area of the triangle ABC, and the area of the tr Evaluate the area of the triangle...