Which one of the following is the correct formula for the equivalent diameter for square pitch?

• A. D = \( \frac{4(Pt^2-\frac{πOD^2}{4})}{πOD}\)
• B. D = \( \frac{4(0.86×Pt^2-\frac{πOD^2}{4})}{πOD}\)
• C. D = \( \frac{(\frac{0.86}{2}Pt^2-\frac{πOD^2}{4})}{\frac{π}{2}OD}\)
• D. D = \( \frac{4(\frac{0.86}{2}Pt^2-\frac{πOD^2}{4})}{\frac{π}{2}OD}\)