To measure the unknown distance x over semi-opposite holes using pins (largest gage pins that can fit into holes) and the number of holes n is odd and greater than 3, and the distance c between adjacent holes (pins) is known as shown left in Illustration C, use the equation:

Where:

c = the distance over adjacent pins
d = the diameter of the holes
θ = 360°/n or angle between adjacent holes.

All units shall be consistant and given in inches or mm. Angles (theta) are given in degrees