Question

Prove that the points (0, – 1, – 7), (2, 1, – 9) and (6, 5, – 13) are collinear. Find the ratio in which the first point divides the join of the other two.

Answer 1

Given; Three points A (0, – 1, – 7), B (2, 1, – 9) and C (6, 5, – 13)

⇒ AB + BC = AC; ∴ Points A, B and C are collinear.

AB:AC = 2√3:6√3 = 1:3

∴ from the lengths of AB, BC and AC we can say that the first point divides the join of the other two in the ratio 1:3 externally.