tolong jawab menggunakan cara nya, terima kasih...

AP / PB = AQ / QC
x / x + 5 = 12 / 16
12(x + 5) = 16x
12x + 60 = 16x
60 = 16x - 12x
60 = 4x
60 : 4 = x
15 cm = x

PB = x + 5 = 15 + 5 = 20 cm