a) Knowing that the coordinates of A, B and C are the following A(-2, 8, 5): B(0, 10, 6): C(4, 5, 5). Using the orthogonal projection, determine the length of AD. (The sides BD and AC are perpendicular.) b) If the length of segment CE is 2, what is the distance between point D from point E? (The sides DE and CE are perpendicular.) C) Determine the angle formed by the sides AB and AC. tant donn la figure suivante, C B A