The inter-conversion relation for Celsius, Fahrenheit and Reaumur scales is:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \(\frac{C}{5}=\frac{f-32}{9}=\frac{R}{4}\)
All three scales divide the same interval, from the melting point of ice to the boiling point of water, into a different number of equal parts. A reading is therefore the same fraction of that interval on every scale.
Celsius: 0 to 100, that is, 100 parts
Fahrenheit: 32 to 212, that is, 180 parts
Reaumur: 0 to 80, that is, 80 parts
Same fraction on each scale: \(\displaystyle \frac{C-0}{100}=\frac{f-32}{180}=\frac{R-0}{80}\)
Dividing every denominator by 20: \(\displaystyle \frac{C}{5}=\frac{f-32}{9}=\frac{R}{4}\)