1. The problem asks to calculate something given that the power factor (pf) is 0.9. 2. Power factor (pf) is defined as the ratio of real power (P) to apparent power (S), i.e., $\text{pf} = \frac{P}{S}$. 3. Without additional information such as real power (P) or apparent power (S), we cannot calculate specific values. 4. If you provide either real power or apparent power, we can calculate the other using the formula $P = \text{pf} \times S$ or $S = \frac{P}{\text{pf}}$. 5. Please provide more details or specify what exactly you want to calculate with pf = 0.9.