Algebra Change of Subject

Sometimes we will need to rearrange a formula to find the value of a subject.

For instance, we may know the area of a circle and need to find the radius. To do this, rearrange the formula to make the radius the subject.

Changing the subject of a Formula

The area of a circle (A) is r²

So A = r²

If we know the radius, it is easy to find the area using this formula. However, if we know the area and want to find the radius, rearrange the formula to make 'r' the subject.

A = r²

[Start by dividing both sides by pi]

[Then take the square root of both sides]

or

Task 1:

You are given 7 minutes to view the following video.

Go through the process of changing subject

Task 2:

You are given 10 minutes to review the introduction and the worked example from worksheet 5.

v = u + at

sources:

gcsebitesize