C = 180° - 40° - 20° = 120°
По теореме синусов:
BC/sin A = AC/sin B = AB/sin C = 2R
BC = AB*sin A/sin C = 9*sin 40°/sin 120° = 9*sin 40°/(sqrt(3)/2)
BC = 18*sin 40°/sqrt(3) = 18sqrt(3)*sin 40°/3 = 6sqrt(3)*sin 40° ≈ 6,68 см
AC = AB*sin B/sin C = 9*sin 20°/sin 120° = 9*sin 20°/(sqrt(3)/2)
AC = 18*sin 20°/sqrt(3) = 18sqrt(3)*sin 20°/3 = 6sqrt(3)*sin 20° ≈ 3,554 см