Given two projections $E_1$ and $E_2$ with $\deg (E_1) = \deg(E_2)$, prove that $E_1$ and $E_2$ are similar projections.

Question

Given two projections $E_1$ and $E_2$ and $\deg(E_1) = \deg(E_2)$, prove that $E_1$ and $E_2$ are similar projections. I'm trying to understand how this sentence can be proved, from which direction should I start the proof, is it by analysing the two projections and the way they are constructed, or that there are some properties that I'm missing? Any hint!