Step 1 :Given the exponential growth function \(f(x)=800(1+0.122)^{x}\), where \(x\) represents the number of months.
Step 2 :Substitute \(x=61.5\) into the function to find the balance after 61.5 months.
Step 3 :Calculate the result to get the balance: \(f(61.5)=800(1+0.122)^{61.5}=949840.5091231895\).
Step 4 :Round the balance to the nearest cent to get \$949840.51.
Step 5 :Final Answer: The balance after 61.5 months would be approximately \(\boxed{949840.51}\).