If the temperature in a refrigerator is set at 45 degrees Fahrenheit, what is this temperature in degrees Centigrade, rounded to the nearest whole degree?

To convert a temperature from Fahrenheit to Centigrade (Celsius), you can use the formula:

[ °C = \frac{(°F - 32) \times 5}{9} ]

In this case, substituting 45 degrees Fahrenheit into the formula gives:

1. Subtract 32 from 45:

( 45 - 32 = 13 )

2. Multiply the result by 5:

( 13 \times 5 = 65 )

3. Divide by 9:

( \frac{65}{9} \approx 7.22 )

When this value is rounded to the nearest whole degree, it becomes 7 degrees Centigrade. Therefore, the reasoning behind selecting the answer is that 7 is the rounded conversion of 45 degrees Fahrenheit into degrees Centigrade using the standard conversion formula.

This demonstrates the necessary conversion process and shows why the answer 7 degrees Centigrade is accurate.