BC = AB - 3/10 = 1/3 - 3/10 = 10/30 - 9/30 = 1/30
AC = AB + BC = 1/3 + 1/30 = 10/30 + 1/30 = 11/30
CD = AC - 27/40 = 11/30 - 27/40 = 44/120 - 81/120 = отрицательное число.
где-то ошибка.
BC = AB - 3/10 = 1/3 - 3/10 = 10/30 - 9/30 = 1/30
AC = AB + BC = 1/3 + 1/30 = 10/30 + 1/30 = 11/30
CD = AC - 27/40 = 11/30 - 27/40 = 44/120 - 81/120 = отрицательное число.
где-то ошибка.