Step 1 :Define the variables where P is the annual payment, r is the annual interest rate, n is the number of times interest is compounded per year, and t is the time in years. In this case, P equals to $600 times 12 which is $7200, r equals to 6.6% or 0.066, n equals to 1, and t equals to 15 years.
Step 2 :Calculate the value of the annuity using the formula \(A = P \times \left( \frac{(1 + r/n)^{n \times t} - 1}{r/n} \right)\).
Step 3 :Substitute the values into the formula to get \(A = 7200 \times \left( \frac{(1 + 0.066/1)^{1 \times 15} - 1}{0.066/1} \right)\).
Step 4 :Solve the equation to find the value of A, which is approximately \$175451.26.
Step 5 :Final Answer: The value of Wendy's annuity when she retires will be \(\boxed{\$175,451.26}\).