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
check it yourself ...
Fahrenheit to Celsius Converter
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
To derive the formula, use the freezing and boiling points of water, to get the slope of the line:
$\displaystyle \frac{\Delta C}{\Delta F}=\frac{100-0}{212-32}=\frac{5}{9}$
Now, use the point-slope formula:
$\displaystyle C-0=\frac{5}{9}(F-32)$
$\displaystyle C(F)=\frac{5}{9}(F-32)$
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.