What is the formula to convert Celsius to Fahrenheit?

What is the formula to convert Celsius to Fahrenheit?

• A. F = (9/5)C + 32
• B. F = (5/9)C + 32
• C. F = C + 32
• D. F = (9/5)C - 32

Answer: (A)

Converting Celsius to Fahrenheit relies on two ideas: where the two scales align and how big each degree is in each scale. The Fahrenheit scale starts 32 degrees higher than the Celsius scale when Celsius is zero, and a one-degree change in Celsius equals a 9/5 (which is 1.8) change in Fahrenheit. Putting those together gives the conversion formula F = (9/5) × C + 32. Checks help confirm it: if C is 0, F is 32; if C is 100, F is 212. The 9/5 factor captures the different sizes of degree units, and the +32 shifts the zero point from 0 C to 32 F. Other forms would either use the wrong slope or the wrong offset. For example, using 5/9 would give too small a change per degree; omitting the +32 would ignore the shift in zero points; and using a minus 32 would move the offset in the wrong direction.

Converting Celsius to Fahrenheit relies on two ideas: where the two scales align and how big each degree is in each scale. The Fahrenheit scale starts 32 degrees higher than the Celsius scale when Celsius is zero, and a one-degree change in Celsius equals a 9/5 (which is 1.8) change in Fahrenheit. Putting those together gives the conversion formula F = (9/5) × C + 32.

Checks help confirm it: if C is 0, F is 32; if C is 100, F is 212. The 9/5 factor captures the different sizes of degree units, and the +32 shifts the zero point from 0 C to 32 F.

Other forms would either use the wrong slope or the wrong offset. For example, using 5/9 would give too small a change per degree; omitting the +32 would ignore the shift in zero points; and using a minus 32 would move the offset in the wrong direction.