Answer:
arc BC = 84 degrees
Step-by-step explanation:
notice:
need to find n before finding arc BC
(13n -16) + (7n + 12) + 6n = 360
13n + 7n + 6n - 16 + 12 = 360
26n - 4 = 360
26n = 364
n = 364/26 = 14
so arc BC = 6*14 = 84 degrees
