1. **State the problem:** We have an initial investment (principal) of $360, invested for 8 years at an interest rate of 9%, and the balance at the end is $1,083.60. We need to find the interest earned. 2. **Formula used:** The balance after interest is given by $$\text{Balance} = \text{Principal} + \text{Interest}$$ 3. **Calculate the interest:** $$\text{Interest} = \text{Balance} - \text{Principal}$$ 4. **Substitute the values:** $$\text{Interest} = 1083.60 - 360$$ 5. **Perform the subtraction:** $$\text{Interest} = 723.60$$ 6. **Interpretation:** The interest earned on the investment over 8 years is 723.60.