NCERT Class 9 Solutions: Linear Equation in Two Variable (Chapter 4) Exercise 4.3 – Part 6

Common Fahrenheit to Celcius conversions

Conversion From C to F

Common Fahrenheit to Celcius conversions

Q-8 In countries like the USA and Canada, temperature is measured in Fahrenheit, whereas in countries like India, it is measured in Celsius. Here is a linear equation that converts Fahrenheit to Celsius.

Equation

  1. Draw the graph of the linear equation above using Celsius for Equation and Fahrenheit for Equation

  2. If the temperature is Equation , what is the temperature in Fahrenheit?

  3. If the temperature is Equation , what is the temperature in Celsius?

  4. If the temperature is Equation , what is the temperature in Fahrenheit and if the temperature is Equation , what is the temperature in Celsius?

  5. Is there a temperature which is numerically the same in both Fahrenheit and Celsius? If yes, find it.

Solution:

Given equation is

Equation

  1. Draw the graph of the linear equation above using Celsius for Equation and Fahrenheit for Equation

    Let temperature in Celsius be Equation and Fahrenheit be Equation

    So the equation will be Equation . Note how this equation expresses temperature in Fahrenheit for a given temperature in Celsius.

    To graph this equation we find a few points:

    • Putting the value of Equation in equation (1)

      Or , Equation

      So the point is Equation

    • Putting the value Equation in equation (1)

      Or, Equation

      So, point is Equation

    • Putting the value Equation in equation (1)

      Or, Equation

      So, solution is Equation

    Therefore graph becomes

    Graph of a line y=(9/5)x+32

    Line Describing Relation Between Celsius and Fahrenhit

    Graph of a line y=(9/5)x+32

  2. If the temperature is Equation , what is the temperature in Fahrenheit?

    If, Equation Equation

  3. If the temperature is Equation , what is the temperature in Celsius?

    So, Equation

    Equation

    Or Equation

    Or Equation

    Or Equation

  4. If the temperature is Equation , what is the temperature in Fahrenheit and if the temperature is Equation , what is the temperature in Celsius?

    • When Equation , Equation

    • When Equation , Equation

      Equation

      Equation

      So, required temperature Equation

  5. Is there a temperature which is numerically the same in both Fahrenheit and Celsius? If yes, find it.

    Equation

    Let the same temperature be Equation numerically. This temperature m in Fahrenheit should be same as temperature m in Celsius, i.e. Equation = Equation . We know that Equation . Therefore,

Let’s solve this equation, Equation

Equation

Equation

Equation

Equation

Equation

Equation

Equation

So, numerical value of required temperature Equation

Explore Solutions for Mathematics

Sign In