panjang AB pada gambar disamping adalah

[tex] \frac{ad}{ab} = \frac{de}{bc} \\ \frac{10}{10 + db} = \frac{8}{12} \\ 120 = 80 + 8db \\ 40 = 8db \\ 5 = db[/tex]

AB = AD + DB
AB = 10 + 5
AB = 15 cm


semoga membantu

AB = AD + DB
AB = 10 + 5
AB = 15