### Video Transcript

Albert Einsteinβs famous formula πΈ equals ππ squared, where π is the speed of light, relates the energy, πΈ, contained in matter and its mass, π. Rearrange the formula to make π the subject.

In order to rearrange or change the subject of a formula, we need to use our knowledge of inverse operations and the balancing method. In this question, as we want to make π the subject, we need to get this letter on its own on one side of the equation. We begin by dividing both sides of the equation πΈ equals ππ squared by π. The left-hand side becomes πΈ divided by π. And the right-hand side becomes π squared as the πβs cancel.

The inverse or opposite of squaring is square rooting, so we need to square root both sides of this equation. On the left-hand side, we have the square root of πΈ over or divided by π. The square root of π squared is equal to π.

Rearranging the formula πΈ equals ππ squared to make π the subject gives us π is equal to the square root of πΈ over π.