Use the simple interest formula to determine the missing value. \[ p=\$ 1775, \mathrm{r}=?, \mathrm{t}=4 \text { years, } \mathrm{i}=\$ 127.80 \] \( \mathrm{r}=\square \% \) (Do not round until the final answer. Then round to one decimal place as needed.)

To find the missing interest rate \( r \) in the simple interest formula \( I = P \times r \times t \), we can rearrange it to find \( r \): \[ r = \frac{I}{P \times t} \] Substituting the given values: \[ r = \frac{127.80}{1775 \times 4} \] Calculating the denominator: \[ 1775 \times 4 = 7100 \] Now, substituting that back: \[ r = \frac{127.80}{7100} \] Calculating \( r \): \[ r = 0.018 \text{ (approx)} \] To express \( r \) as a percentage, multiply by 100: \[ r = 0.018 \times 100 = 1.8\% \] So the interest rate \( r \) is \( 1.8\% \).