1. The problem asks to convert Grethe's temperature from Celsius to Fahrenheit. 2. The formula to convert Celsius ($C$) to Fahrenheit ($F$) is: $$F = \frac{9}{5}C + 32$$ 3. Substitute $C = 39.5$ into the formula: $$F = \frac{9}{5} \times 39.5 + 32$$ 4. Calculate the multiplication: $$F = \frac{9}{5} \times 39.5 + 32 = 1.8 \times 39.5 + 32$$ 5. Multiply: $$F = 71.1 + 32$$ 6. Add: $$F = 103.1$$ 7. Therefore, Grethe's temperature in Fahrenheit is **103.1°F**.