1)claculer AC 2)en deduire AD (Formule cosinus)

1) cosC = BC/AC
   cos30 = BC/AC
   (V3/2) = 5/AC
AC = ≈ 5,77cm

2) cosD = AD/AC
   cos 40 = AD/AC
   0,766 = AD/5,77
   AD = ≈ 4,42cm
   0,766