14. TA CÓ 1. SINS 2AB BC B B S   2 2.9, 69 0SIN SIN 50. 4, 6.5,...

5.14. Ta có 1. sinS 2AB BC B B S   2 2.9, 69

0

sin sin 50. 4, 6.5, 5AB BCVậy B50 .