# Can I use per unit method for true, reactive, and apparent Power

I would like to show apparent power (S) in Cartesian coordinate system with a circle of radius 1, where x axis represents reactive power (Q), and y axis represents true power (P). There's the formula:

P^2+Q^2=S^2


Can I use these formulas to transform it in per unit system:

P[p.u.] = P / S
Q[p.u.] = Q / S
S[p.u.] = S / S = 1