If the position vectors of the vertices a, B and C of a `Triangle ABC` be `(1, 2, 3), (-1, 0, 0)`
Channel: Doubtnut
Date: 2020-04-19

If the position vectors of the vertices a, B and C of a `Triangle ABC` be `(1, 2, 3), (-1, 0, 0)` and `(0, 1, 2)` respectively then find `angleABC`.