MathematicsHard202×since 2002Q5768Let A (3, 0, –1), B(2, 10, 6) and C(1, 2, 1) be the vertices of a triangle and M be the midpoint of AC. If G divides BM in the ratio, 2 : 1, then cos (∠\angle∠GOA) (O being the origin) is equal to :A115{1 \over {\sqrt {15} }}151B1610{1 \over {6\sqrt {10} }}6101C130{1 \over {\sqrt {30} }}301D1215{1 \over {2\sqrt {15} }}2151Check answerSkip