First, I suggest drawing a picture of what the problem says so you can see what I'm talking about.
I would upload one, but I can't right now on this computer.
tan = opposite / adjacent
Plug in the numbers you know.
tan 43º = AC / 9.3
Multiply both sides by 9.3 .
9.3tan43º = AC
Put this into a calculator to get that
AC ≈ 8.672
You had it right!! 