# Thread: changing celsius to F

1. ## changing celsius to F

45.7°f = what in celsius

Is this the equation I should be using

C = °F-32/1.8
C= 45.7-32/1.8= 7.6

2. ## Re: changing celsius to F

check it yourself ...

Fahrenheit to Celsius Converter

3. ## Re: changing celsius to F

Originally Posted by Louisana1
Is this the equation I should be using

C = °F-32/1.8
C= 45.7-32/1.8= 7.6
The equation is wrong as written, though the answer 7.6 is (approximately) correct.

4. ## Re: changing celsius to F

Your answer is correct but the correct equation for Fahrenheit to Celsius is :
(F - 32) x 5/9 = C
where F=45.7
Thus,
(45.7-32)*5/9=7.6

Composition of Functions

5. ## Re: changing celsius to F

To derive the formula, use the freezing and boiling points of water, to get the slope of the line:

$\frac{\Delta C}{\Delta F}=\frac{100-0}{212-32}=\frac{5}{9}$

Now, use the point-slope formula:

$C-0=\frac{5}{9}(F-32)$

$C(F)=\frac{5}{9}(F-32)$

6. ## Re: changing celsius to F

Originally Posted by Louisana1
45.7°f = what in celsius

Is this the equation I should be using

C = °F-32/1.8
C= 45.7-32/1.8= 7.6
You mean C= (F- 32)/1.8. What you wrote really means C= F- (32/1.8)
You can check that is correct by checking the "easy values". The freezing point of water is 0 C and 32F:
(32-32)/1.8= 0/1.8= 0 so that is correct.
The boiling point of water is 100 C and 212 F:
(212- 32)/1.8= 180/1.8= 100 so that is correct.

Since this is a "linear" equation and two points determine a line you know that is the correct formula for any F.