Please help with this question!

Answer:
The answer to the question is a.
Step-by-step explanation:
We can use proportion to solve this.
[tex] \frac{5}{6} = \frac{5}{x + 3} \\ 30 = {5(x + 3)} \\ \\ 30 = 5x + 15 \\ \frac{ - 15 = \: \: \: \: - 15}{ \frac{15}{5} = \frac{5x}{5} } \\ \\ x = 3[/tex]
X = 3
BC = 6
AC = 12