Square (multiply by itself) the diameter of each strand (0.32 × 0.32 = 0.1024) Multiply this result x (Pi) 3.14 (0.1024 x 3.14 = 0.321536) Divide this result by 4 (0.321536/4 = 0.080384) Multiply this result by the number of strands (0.080384 x 14) Therefore the approximate area for 3mm auto cable is: 1.13mm².