Răspuns :
AB = 18 cm.
C ∈ (AB), AC / CB = 2 / 7.
AC = ? , CB = ?
AC + CB = AB = 18, AC = 18 - CB.
18 - CB / CB = 2 / 7, (18 - CB) 7 = 2 CB, 126 - 7 CB = 2 CB, 126 - 9 CB = 0,
9 CB = 126, CB = 126 : 9, CB = 14 cm.
AC = 18 - 14 = 4 cm.
C ∈ (AB), AC / CB = 2 / 7.
AC = ? , CB = ?
AC + CB = AB = 18, AC = 18 - CB.
18 - CB / CB = 2 / 7, (18 - CB) 7 = 2 CB, 126 - 7 CB = 2 CB, 126 - 9 CB = 0,
9 CB = 126, CB = 126 : 9, CB = 14 cm.
AC = 18 - 14 = 4 cm.