The bending performance equation P C R = σ / ρ {\displaystyle P_{CR}={\sqrt {\sigma }}/\rho } can be treated similarly. Using the power property of logarithms it can be derived that log ⁡ ( σ ) = 2 × ( log ⁡ ( ρ ) + log ⁡ ( P C R ) ) {\displaystyle \log(\sigma )=2\times (\log(\rho )+\log(P_{CR}))} . The value for P C R {\displaystyle P_{CR}} for bending is ≈ 0.0316 in Figure 3.