1. **State the problem:** Aaron purchased a shirt that originally costs 1.65 but received a 10% discount. We need to find out how much he actually paid. 2. **Formula for discount price:** The price after discount is given by: $$\text{Discounted Price} = \text{Original Price} \times (1 - \text{Discount Rate})$$ where the discount rate is expressed as a decimal. 3. **Convert the discount percentage to decimal:** 10% = 0.10 4. **Calculate the discounted price:** $$\text{Discounted Price} = 1.65 \times (1 - 0.10)$$ $$= 1.65 \times 0.90$$ 5. **Multiply to find the final price:** $$1.65 \times 0.90 = 1.485$$ 6. **Interpretation:** Aaron paid 1.485 for the shirt after the 10% discount. **Final answer:** $$\boxed{1.485}$$