Respuesta :

Answer:

Step-by-step explanation:

since arc BC is 2 time the angle of A   , then

2(9x +12) = 21x +3

18x +24 = 21x + 3

21 = 3x

7 = x

x = 7

∠BAC = 9(7) +12

∠BAC = 63 +12

∠BAC = 75°