If the vertices A, B, C of a triangle ABC are (1, 2, 3), (–1, 0, 0), (0, 1, 2), respectively, then find ABC, [ABC is the angle between the vectors ].

Given points are A (1, 2, 3), B (-1, 0, 0) and C (0, 1, 2)


ABC is the angle between vectors










We know






ABC = cos-1(10/√102)


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