1. **State the problem:** Benjamin invests money in a bank account with compound interest. After 2 years, the amount is 658.20, and after 5 years, it is 710.89. We need to find the annual interest rate as a percentage to 1 decimal place. 2. **Formula used:** The compound interest formula is: $$ A = P(1 + r)^t $$ where $A$ is the amount after $t$ years, $P$ is the principal (initial amount), and $r$ is the annual interest rate (as a decimal). 3. **Set up equations:** From the problem, after 2 years: $$ 658.20 = P(1 + r)^2 $$ After 5 years: $$ 710.89 = P(1 + r)^5 $$ 4. **Eliminate $P$ by dividing the second equation by the first:** $$ \frac{710.89}{658.20} = \frac{P(1 + r)^5}{P(1 + r)^2} = (1 + r)^{5-2} = (1 + r)^3 $$ 5. **Calculate the left side:** $$ \frac{710.89}{658.20} \approx 1.0799 $$ 6. **Solve for $1 + r$:** $$ (1 + r)^3 = 1.0799 $$ Take the cube root: $$ 1 + r = \sqrt[3]{1.0799} $$ 7. **Calculate cube root:** $$ 1 + r \approx 1.0262 $$ 8. **Find $r$:** $$ r = 1.0262 - 1 = 0.0262 $$ 9. **Convert to percentage:** $$ r \times 100 = 2.62\% $$ Rounded to 1 decimal place: $$ 2.6\% $$ **Final answer:** The annual interest rate is **2.6%**.