Sometimes you need to rearrange the formula to find the value you're looking for.
The area of a circle ( ) is .
This is useful if we know the radius of the circle and want to know the area. But what if we want to find the radius?
We need a formula that has (some expression in ). We get this by rearranging the formula like this:
Start by dividing both sides by :
Then find the positive square root of both sides:
Swap the sides to make it easier to read:
The formula has been rearranged. We say that now is the subject.
Q1. The formula to find the circumference of a circle:
Rearrange the formula to make the subject.
Q2. The formula to convert the temperature in to the temperature in is:
Rearrange this formula so that it will convert the temperature in to the temperature in (so that is the subject).
A1. , so divide both sides by :
multiply by :
divide by :