translate English to French: 18.7.1.2 (a) Replace "31 ± 1 cm" with "310 ± 10 mm", "61 ± 1 cm" with "610 ± 10 mm" and "38 cm" with "380 mm" (twice).
18.7.1.2 a) Remplacer "31 ± 1 cm" par "310 ± 10 mm", "61 ± 1 cm" par "610 ± 10 mm" et "38 cm" par "380 mm".