1. **State the problem:** We need to find the sales tax percentage when a $5 item costs $5.20 after tax. 2. **Formula:** The total price after tax is given by $$\text{Total Price} = \text{Original Price} + \text{Tax Amount}$$ or equivalently $$\text{Total Price} = \text{Original Price} \times (1 + \text{Tax Rate})$$ where Tax Rate is in decimal form. 3. **Set up the equation:** Let the sales tax rate be $r$. Then: $$5.20 = 5 \times (1 + r)$$ 4. **Solve for $r$:** $$\frac{5.20}{5} = 1 + r$$ $$\cancel{\frac{5.20}{5}} = \cancel{1 + r}$$ $$1.04 = 1 + r$$ 5. **Isolate $r$:** $$r = 1.04 - 1$$ $$r = 0.04$$ 6. **Convert to percentage:** $$r \times 100 = 0.04 \times 100 = 4\%$$ **Final answer:** The sales tax percentage is **4%**.