Теорема косинусов: a²=b²+c²-2bc*cosα, где a,b,c - стороны треугольника, α - угол между b и c.NK² = NM²+MK²-2MK*MN*cos∠NMKNK² = 36+100-120*cos120°NK² = 136 + 120*sin30° = 136 + 60 = 196NK = 14NM² = NK²+MK²-2MK*NK*cos∠NKMcos∠NKM = (MK²+NK²-MN²)/(2MK*NK)cos∠NKM = (196+100-36)/(2*10*14) = 260/280 = 13/14∠NKM = arccos 13/14KM² = NK²+MN²-2MN*NK*cos∠MNKcos∠MNK = (MN²+NK²-KM²)/(2MN*NK)cos∠MNK = (36+196-100)/(2*6*14) = 132/168 = 11/14∠MNK = arccos 11/14