Suppose $\$ 8,000.00$ grows to $\$ 12,100.00$ in 5 years. What is the annual interest rate if interest is compounded semiannually? Enter your answer as a percentage rounded to the nearest hundredth of a percent. Assume the interest rate does not change while the account is open.

Step 1 ：Given that the initial amount (P) is $8,000, the final amount (A) is $12,100, the interest is compounded semiannually (n = 2), and the time period (t) is 5 years.

Step 2 ：We can use the formula for compound interest, which is \(A = P (1 + r/n)^{nt}\), where r is the annual interest rate.

Step 3 ：We can rearrange this formula to solve for r: \(r = n[(A/P)^{1/nt} - 1]\).

Step 4 ：Substituting the given values into the formula, we get \(r = 2[(12100/8000)^{1/(2*5)} - 1]\).

Step 5 ：Solving this equation gives us \(r = 0.08448864641294529\).

Step 6 ：Converting this to a percentage and rounding to the nearest hundredth of a percent gives us an annual interest rate of 8.45%.

Step 7 ：Final Answer: The annual interest rate, when compounded semiannually, is approximately \(\boxed{8.45\%}\).