Answer: 21
Step-by-step explanation:
arc AC = 2b
3x + 9 = 2(3x - 1.5)
3x + 9 = 6x - 3
solve for x
6x - 3x = 9 + 3
3x = 12
x = 4
substitute in the 2 equations
3 (4) - 1.5 = 10.5
which means that if we substitute in the second equation we should get 21
3(4) + 9 = 21
so arc AC= 21 degrees
